I echo everybody else's enthusiastic "go kilt"! But I also urge you, as Standard has, to immediately check with the principal of the school regarding a prom dress code. Many schools have them and they are, uh, [kindly put] often unbelievably narrow-minded if not downright straitjacketing. And, some administrations simply refuse out of hand to hear anything other than what they deem appropriate. Now, if you come from a progressive school district, it's great. If you don't, don't be surprised or take it personally if it's not possible to budge the school administrators. The folks who may refuse you your kilt are usually the ones not necessarily interested in ethnic awareness or any other sensible argument; they're unfortunately out for their own necks and to dissuade students from nonconformity of any sort. It's not your fault if you aren't allowed the kilt for prom.

'Nuff said. Go talk with the Powers that Be and let us know what you find out.
Good Luck!