The age gap is really big. Imagine dating someone as old as your parents. But then again it's fine since he isn't indulging her in a sexual relationship or what not.
The age gap is only a problem for me if the older person is indulging the younger in a sexual relationship, and that doesn't seem to be the case. I really loved that he wasn't some perv after a high schooler, but he fell for her because of who she is, not because she is young. This story is really one of the best oneshots I read. I loved everything about it. And that boy she rejected was so understanding, I'm really glad this story didn't need a villain.
It was cute and even though he was 40 he was hot but so was her dad...lol, looking past the age difference, this was a sweet oneshot. I wished there was more.