Hi Jessica,
My heart goes out to you. Just wanted to say that it doesn't matter how young or old you are, there are many of us on this site that know, and understand exactly what you're going through, and how you feel right now. I can understand that you feel you will have more in common with someone your own age, so why not post on the "teen only" forum, I'm sure there'll be many others there that you can talk to about your concerns, and many who will be more than willing to give you support and encouragement to help you lose weight.
Don't forget that we're all wanting the same thing here ... to be happy with ourselves ... and I'm sure you'll find all the help here that you need. Just keep posting ... and Good Luck to you!!
Nichola