Hi Meagan, and welcome to WLF. It's good you're doing something about your weight now, rather than waiting untill you're much older.
There are a couple of things you might do to get started:
1) start your own journal in that forum. That way, people will be able to comment on your issues.
2) post something in the "Harsh Truth" forum. Hopefully, either Leigh or Steve will answer, and both of them have tons of useful advice.
Just as a warning, keep in mind that the vast majority of posts here are aimed at adults, that is, people whose bodies have stopped growing. You are entering some of your highest growth years, so whatever advice you read about has to be tempered with that in mind.
I personally don't know squat about advising adolescents, so I'm going to defer to the experts who do.