So either her birthday is between April and July or she is lying about her? lol
Probably let's not derail the thread too much about Rose's age, as it's basically an unverifiable fact, we will never know her exact age.
To my understanding, Destiny started sexting with Rose when Rose had "18" in her twitter profile/bio, over the course of their sexual relationship she apparently turned 19, and she updated the bio when she eventually turned 19, if I'm not mistaken.
Most people mention her being 19, because she was supposedly 19 around July/September, which is when Destiny told her everything about his affair with Lauren Southern, so that point in time is used as reference to her age, and when the sexting took place, when to be more accurate, Destiny started sexting her when she had 18 in her profile, and Destiny believed her to be 18.
Now, the problem is that Solo, the leaker, who although is the catalyst of this whole thing becoming publicly known seems to either be protecting Rose or hiding certain details for unknown reasons so we don't have a full picture, but he alleges that Rose was actually 17 when she started sexting with Destiny, she just lied about her age to be able to sell her porn online and Destiny wasn't aware of her being underaged.
So in short:
-Rose is referred as being 19 years old, as that was her age when Destiny told her about the Lauren Southern affair, which is what started to leak first.
-Rose said her age was 18 when she started her sexual relationship with Destiny, so it would be more accurate to call her "the 18 year old", as that's when the sexting started.
-Solo says Rose was actually 17 when the sexting started, instead of 18. However, Destiny wasn't aware of this fact.
Hope that clears up most of the ambiguity of why Rose so often changes ages when being discussed.
I hope I'm not misremembering any of the details.