Just go for it man. Forget what these people are saying. Ok there is an age difference AND the teacher student thing HOWEVER he is about to graduate. There is a teacher at my school who was asked (I live in the south at a private Christian school so I think this would be the best example) by a student on a date in his senior year and they actually went out for a bit after he graduated (she was about 28-29 I believe). People didn't really care about it and no one holds it against her or anything even though it's known. This is a PRIVATE CHRISTIAN SCHOOL where the administration would pretty much kick a teacher out for anything they found "inappropriate" so I think you are safe. I really wouldn't worry about it just go for it. Worst case it doesnt' work out and you are out of school forever in a few months, nothing to worry about.