Hey, welcome to the forum!
I think it's a bit hard to just state "good" reasons to wear a kilt without knowing anything about your father or his reservations about the kilt. Is it simply him wondering why you would be interested in this? Then you should def follow McMurdo's advice. My father would never wear a kilt, but is very supportive of my wearing it (good-natured ribbing aside). I think part of it is just the fact that he knows how snazzy I can look in it and I'm not normally one to dress up.
Is there another reason he might have reservations about the kilt? Then we can tailor our advice to fit the need. Good luck with this!