Fashion: high school??? (:?

Well.. anyways.. im going to be a freshman next year and Im really scared on what kind of stuff to wear. In jr. high we had uniforms for two years (ughh) buhh I kinda need some advice on what to buy (in particular) for high school. My friends a cheerleader and she said that you bring an oversized purse?? Im sure shes right cuhs hers is adorable buhhh.. I need some other advicee (: thanks. Oh.. and if ya find anything cute on the internet juss attach it. Anyways thanks;)