When I was a senior, I dated a sophomore. But she had turned 16 at the time. I was 17. That's not wierd. A senior with a freshman I would think wierd, but then again, times have changed since I was in highschool 10 years ago.
When I was 25 I dated an 18 yr old, that's probably the youngest I had ever dated. And I'll tell you right now, I don't think I'd ever do it again. There was such a huuge gap between priorities and maturity. It felt I was going out with a friggin high school girl. Definitely wasn't worth my time.
My girl, which I've been with for almost 2 years now, is 23 while I'm 28. The older you get, differences in ages matter less and less. It's just that when you're younger, like in highschool, those difference seem huge b/c of the differences in maturity.