It depends. In my middle school, I think all the girls accidently bought the scraps of some fabric because I don't think shorts are supposed to be that short. JK. But, wear something that compliments you and you feel comfortable with while still making you look good.
Depends on what grade your in, and what clothes you got, but personally I would go with, a cropped long sleeve with a tank underneath, skinny jeans, and flats (I wear my TOMS) but it mostly depends on what ya got :)