Funny thing is, I didn't think I'd grow past high school, but after just finishing my sophomore year of college (credit-wise), I grew a little more than an inch or two (maybe an inch and a half... haven't really measured myself to make sure, but everyone's been telling me how much taller I look). I came home a lot more out of shape than I used to be but had a much easier time dunking, because I grew to about 6'6.5" or so since September when I was around 6'4" and change.
So really, you never know when you'll stop growing, and it makes your height at the age of 15, 16, 17, etc. more irrelevant.