I want to change my style?

I'm turning 13 this summer and I'm not even in cup bras. I wouldn't care except for the fact that this limits my clothing options. I tend to wear a lot of graphic tees, like the ones they sell at David and Goliath. I really want to change my style to something a lot girlier and prettier. It's hard because not much fits me. Please leave any suggestions that you have.