Age differences are more important when you're teens because a person changes a lot, and becomes much more mature(emotionally and mentally) over the course of just a year or two. However, it's really not a problem unless one of the partners is uncomfortable. If both partners are fine with it, it's not a problem in my mind. Culturally, I think our culture is uncomfortable with the idea of "underage" individuals dating at all, and that stigma carries over to even small age differences of a year or two, when one of them is under 18. That's my $0.02