“Oh, sorry!”
This was a common phrase [This is telling, not showing. An important principle to remember is that the action you introduce your character with is the action we will forever associate with that character. First impressions are very real. If you introduced Waki as eating a cake, we'd think of her as the fatass. Since you introduce her apologizing, the readers automatically have the image of a character who apologizes a lot.] for Waki Kurayami, presently [When you say a character is doing something, that's already implied that it's happening in the present of the narrative. Reading is a linear narrative , the natural progression of a sentence and paragraph from left to right is already interpreted as the passing of time. You only need to state that something is happening in the present if you're breaking out of a flashback or flashforward or daydream or any other temporal weirdness.] skating by a teenage couple holding one another as they moved along the side of the rink. [Is this an important detail? Otherwise, the reader right now is following Waki's movement. Bringing up the movement of others will break the reader out of that. It's a frame of reference, sort of thing. Waki is faster than them, thus she's passing them, thus that's all that matters.] In spite of the couple being unconcerned with the rest of the world around them, the urge to apologize (often) was an unfortunate part of Waki’s behaviour. Still, the young lady kept up her brisk pace, her small and athletic build allowing her to effortlessly glide through the small gathering of people that shared the rink with her, occasionally saying "sorry!" or "excuse me" to those she passed by. [The prose here is pretty fine, it's just too many ideas in one sentence. A run on, in other words. I'd cut this up into three sentence of varying length.] This was essential [If the narrator is telling us that something is the case, then the reader will assume that it is essential. There is a trust relationship between the narrator and reader that the narrator will cut out all unnecessary details that don't build the world further.] as it allowed the chill of the late fall to hit her, with the school clothing she wore, covered only by an unbuttoned, tight, black cardigan, being unable to prevent the breezy rush her skin craved. [This suddenly jumps into passive voice which should always be used with careful intention. Active voice is "Waki drank tea." Passive voice is "The tea was drunk by Waki." Also the prose here is just a bit odd. Is it important that she's wearing a black cardigan? Is it important that it's unbuttoned? If it's a key character detail, then just a passing mention of the black cardigan like "the wind pierced her black cardigan" would be better than halting the action to describe it.]
Following a few more minutes of skatework, [This falls back to that time thing I mentioned. Yes, you can do this, but it should be for unimportant actions like eating breakfast or walking down the street. It just seems weird to handwave the skating after setting it up. Also this is a great chance to show more of Waki's personality. If you want to express the passing of time without outright saying it and taking advantage to flex your literary muscles, spending a paragraph describing how she was skating, what she did, what more she noticed, will illustrate time and Waki herself. Longer paragraphs are read as more time passing, naturally.] Waki glided to an empty part of the rink, twirled smoothly around, and began to [Don't say a character began to or started to do anything unless you're trying to delay its occurrence in the narrative by a few seconds via that time thing I mentioned before or if they're going to be interrupted or stopped. In other words, only when it's important that they stop and don't complete the action or if there's a hesitance to it, or some other reason like that.] skate backwards. She then [Time thing again. You don't need to tell us that something is happening after the actions of the previous sentence. It's already assumed. There are circumstances when you should do this, but those are almost entirely flow reasons and flow is something that should be worked on in the final stages of editing.'] found the single set of eyes that were following her in the rink. [This isn't a big thing, but to me, the narration as been reading as limited within Waki's perception. It seems weird that she'd know that there was only one person watching her.] Her bright, blue eyes quickly set themselves on a brown pair, her confident skating not disappearing during this encounter. [This is just purple prose and it's honestly a bit nonsensical. Don't try to show off fancy word play, just say it how it is. You probably don't even need to tell us that she's still skating well, most people would assume that she's still presenting her pre-established trait of being a good skater. You usually only need to point out something like this if there is a change, like she startles but still skates well, or if she had an off-day skating the last chapter and can now skate well again.]
“Heh, Youko, one day I need to teach you how to skate backwards!” This girl was leaning over the top of the rink's rigid wall, [Passive voice again. Also Waki is the speaker of that dialogue. Rule of thumb is nearly always when a character says something and an action happens, if the speaker is performing the action, then you leave it in the same paragraph. That's an easy flow of idea and information for the reader. If the speaker says something and someone else performs an action in response, it should be a new paragraph since that symbolizes and reads as a break in the context/flow of info. For example:
"I'd like that!" Waki pointed at the bottle.
vs
"I'd like that!"
Waki pointed at the bottle.
The first one is pretty clear to read and understand. There is a physical connection on the page on being within the same paragraph. The second one is more ambiguous. The speaker might be Waki, or it might be someone else and Waki might be pointing at the bottle to clarify. Who knows.]
swinging her skates with her right hand. She was ready to depart for home, but decided to wait on Waki, who had desired to skate for a few minutes longer. [This is telling and not showing. You can show easily via expressing this in dialogue.]
“Man, you’ve been so full of energy the last week or so.” leaning farther into the rink. “That because your momma’s coming back from her business trip today?” [When doing a compound dialogue thing like this, commas are usually your friend. Of course, not always. If you want to illustrate a pause or an important end of the thought, then use a period. But here, you'd want a comma. Also the action of 'leaning farther into the rink' doesn't have a subject. I know it's Youko, but it's still jarring. The reader should never have to stop and figure out who or what the subject is. There's nothing wrong in framing this simply as '"... or so," Youko leaned further over the railing, "That because..." It's a lot simpler, but readers don't read to get flexed on or be wowed by prose work, they read for a story. The prose is just the tool to achieve that.]
Then [Time thing again. It's happening later on the page, thus it's happening later in the narrative.] Waki, still backwards, [You haven't made note of a change, thus she is still backwards in the narrative even without a note being made and most readers would still picture her as backwards.] made course for her friend. Another twirl later, and she had [This is the same thing as that "began to" and "started to" thing along with any other bridge words. Use them very intentionally.] brought her flight to a stop, her smiling face a [What you're doing here isn't always wrong, it's just weird here because it makes it seem like her face is seperate from her body. There's not really a reason to put emphasis on her face and her smile. Judging by their friendly dialogue, we can already assume that she's smiling or you can slide it into the next paragraph's speech tag.] few feet from Youko.
“He he...yep, that she is! I’ve missed her so much…” Waki began [Same thing as before. Also use ellipses sparingly. If there's an adverb or adjective to describe her speech pattern, use it. After a while, seeing ellipses over and over will make them fade into white noise and become meaningless to the reader. They should only be used for impact. Also most boomers text with too many ellipses and the last thing you want is people associating your YA fantasy with their dad texting about picking up gas for the mower.] fidgeting with one of her cardigan’s buttons. “Sorry if I’ve been weird or anything lately…” With a tiny sigh, Youko stood herself up. [It's that dialogue - action thing I mentioned before. This should be a new paragraph because it's a new thought.]
“Gosh, how often do I gotta tell you not to apologize all the time?” Youko said, slightly shaking her head left and right. [There is only one way to shake your head and that is left and right. Otherwise it is a nod or a seizure. Don't need to tell us that it's left and right.] Waki shrugged her shoulders a tiny bit, but was unable to respond before Youko resumed her questioning. [This is telling and not showing again. You can use that 'started to' thing here. Like 'Waki started to stammer a response" then immediately jump into the next paragraph of Youko's response.]
"You think, [cause with no apostrophe is like "this was the cause of the consequence". With an apostrophe is the shortened version of because. Apostrophes mark a contraction.] cause she was away on her trip, that she's gonna bring you something awesome back as a late birthday present?" Waki perked her head up, and brought her hands up to just below her chin. [Dialogue - action thing again.]
"Oh my goodness! That would be so cool!” she chirped, jumping up, and struggling to keep balance once she landed back on the ice. [That sentence should end at jumping up because that's the end of that action. The struggling to keep balance is a new action as a result of the previous one. Time has passed from her jumping and her landing and struggling. Also the time thing plays even more here. Right now her struggling is coming across as occurring before the landing. It's fine to play with time and cause and effect like this, but again very intentionally. I'd rephrase that whole "struggling to keep balance" part because it comes across as telling again. Say that her foot nearly slipped as she landed or that she wobbled as she landed. Don't need to tell us that she's on the ice unless she jumped over the railing onto the concrete.] Unintentionally, her right arm, decorated with her custom black and white Zeeko watch, was brought close to her face. [Passive voice again. Also how does one unintentionally bring their arm up to look at their watch? If you mean that she put her arm out to keep balance, then caught sight of her watch, then say that. Say that she grabbed onto the railing maybe. I get that the watch is important, but it's really shoved in here and it ruins the flow and pacing. I'd find a better way to weave it in.] .“Oh, I should get home and get things ready for her!" Thus, [It's logical that she would rush to leave after that statement. You don't need to point out that it's connected with a connection word. Thus is also a time word . We already knows that Waki leaving happens after her dialogue.] Waki rushed to the rink's exit, a few feet from Youko. Ungracefully power walking in her skates, she addressed a quick goodbye to Youko. [Telling not showing again. There is only one other actor in this scene and that's Youko, so we already know that she's talking to Youko. We know from the dialogue that it's a goodbye, so you don't need to tell us. The ellipses show up here again and that contradicts the quickly part of it. I think you can just say "...Youko!" she quickly said, nearly falling as she stopped suddenly." There's also passive voice in "sudden stop she made" so get rid of that. ] "He he...see you on Monday, Youko…!" she said, almost falling over from the sudden stop she made.
A smile had formed on her friend’s face, and she chuckled alongside answering back to Waki.
[Passive voice. Youko smiled as she chuckled. Bam. That's all you need. Then in the same paragraph, have her say her dialogue so it connects.]
"See ya! Oh yeah, make sure you tell me everything that goes down, K?" she said, beginning to make her way to the exit. [Who is this she? Is it Youko? Or Waki? Why are they saying goodbye if they're both going for the exit? Also K is the letter. 'Kay is the abbreviation of Okay. The beginning is fine here since the dialogue occurs within the start of the action. It works as framing.]
As she removed her skates, she found her thoughts take on an introspective tone. She wondered why Youko was always so upset at her constant apologizing.
“It’s just the nice thing to say, is all. Besides, I’m usually in the right anyway.” [This is a non-sequitur. There's no logical reason why she would think of this now. You can easily fix this by having her apologize for leaving suddenly and ditching Youko then have Youko tell her not to say sorry, then this. Also "she found her thoughts take on an introspective tone" and "she wondered why" is telling and not showing. You can just say As Waki removed her skates, she sighed. Why did Youko always get upset about her apologizing?" And framing this with the "she thought' is weird because this chapter's narration is already limited within Waki. Limited narration rarely every needs a the focal character to have a thought tag. You can just write the thought in like I did before.] She thought, as she passed from the warm entrance of the rink, to the soothing chill of the September winds. [Earlier in the chapter you said she was hit by the Fall chill. But now she's inside in a warm rink? Just a consistency thing.]