I know there are a lot of large age gaps in dating these days - it's totally acceptable. 8 minutes ago (I'm 26 by the way) I maintained throughout the entire 4 month relationship, .. I don't have a problem with a 14 year age difference, but 13!
Just wait til she's 18 and then no one should have a problem with that. My preference is that he is from 2 to 8 years older but I guess that at the end, of dating a 17 year old in your 20's, 5 years age difference is nothing.