Age of consent when the older partner is 20 is way under 18 in most of the US.
I dated a lot of high school girls (16 and 17) when I was 19 and 20, it wasn't because I was a "predator", it was that they were nice girls, and thats all I ever met (every girl over the age of 17 in my circle of friends went away to college at 18).
So I really don't see anything wrong with that.