Someone allready asked what i was going to ask (What does the school say about you wearing a kilt?),but I don't think you ever said.
I know most schools frown on it and even deny wearing of a kilt.
It can be beat under discrimination,but if your under 18 your parents would have to be envolved,an well, we are ready know where your dad stands.

So if this is the case,forget it untill your in college an on your own,than do what ever you want.