The whole thing sounds fine as long as the level of dress is appropriate for the occassion. I personally think that a kilt adds a touch of dressiness to an otherwise casual outfit. In this case, a man in a pair of trousers with the same shirt, tie, and vest won't look as dressy as you in a klt.

(I know some folks feel they can--and they really can--wear anything they like anywhere, but that's not me. I am somewhat more conservative and prefer to dress in the manner generally deemed appropriate by the regulars of that event. I would err on the side of being overdressed rather than the other way.)

Of course, since you have so much time, you can also investigate buying a nice used jacket at the local Goodwill or Salvation Army store and have it tailored for a reasonable fee. That would give you a very nice kilt jacket as an alternative.