I didn't start the "teenage sprout" until I was 15. Was tiny light and short until then. I'm 21 now, but I stopped around around 17 - 5"10. Got to 5"11 by 19, I reckon I've levelled out now. Depends how I sleep and exercise, but I'm between 5"11 and 6".
Went to an international school where people weren't only coming from the southern hemisphere, but also being held back if they didn't pass years, so I ended up at 14, in rugby class with 17 year old NZ brutes that lived in the gym and fed on... idk what the **** they fed on. But they were brutes. It was rather unpleasant. Think of it like tennis. Except I was the ball.