Took a break from studying
The way I see it this show is aimed at pre-teens, aang is at the age where boys start to notice girls. I don't see anything wrong with Katara and Anng as a couple, theres nothing wrong in dating someone 2 years older. Plus they're really just kids, they're not going to go off and have wild sex. It's just a crush, for the time being.
Another thing is, I think they have more important things to focus on than each other. The only way I see them together is after this is all over and there is a 10 year later epilogue.