I had a high school experience that was probably 70% bad and about 30% good. But as time has passed, I find myself mostly fixated on the good times because of nostalgia berries and the fact that I can detach myself away from the bad shit and focus on the good times.
That being said; one moment stands out for me as the moment that I realized I was done with high school. It was senior year/spring 1999 and we were doing the annual awards ceremony assembly for the senior class. It takes up the bulk of the morning of the day and afterwards, while everyone else has to go back to the rest of their morning classes and regular schedule, the seniors get to go to the home ec room for punch and cake before going to lunch and their afternoon classes.
I'm sitting there and there are a lot of us there and I'm sitting across from like three people I had not had any real interaction with since around 5th or 6th grade. It's about a four weeks before graduation and I look around to all sorts of people milling about and I realized something: I'm never going to see 99% of these people ever again.
When I went to the local university, about 10% of my class went there and only about 5% of them actually graduated. I rarely saw them except from a distance on campus and the disconnect was more severe due to the fact that I was the only one of my graduating class going to said college, that lived on campus. Everyone else was commuting back and forth every day.
But back to that after awards "party" in the home ec room. That was when I was "over" high school. In an existential moment when you realize, that the eco-system you lived in for your entire life, a support system that was both good and bad, was going away. Gone. All those social ties that you take for granted, the people who've been in your life both as friends, foes, or "That guy/gal"; the casual acquaintances and people you had superficial friendships with, along with those people who treated you like dogshit and that made you wish horrible things happen to them as a result of their cruelty towards you? Gone. All gone. And the only thing you can do is chin up and move forward, always moving forward because you can't freeze time or change the past.
The only way to describe that moment would be this song: