Diana is right, you're young and really should have quite a bit of energy to help you lose the weight.
I so wish I would have paid more attention when I was younger. You know, I hate to admit this, but the first time (right after I married) that I gained a bunch of weight, I didn't even remember changing sizes!
How blind is that? I wish I would have paid more attention. I do pay attention now! I'm not going to gain anymore....but it sure is hard to take it off being in my 50's.