i'm really not sure...i have a shit opinion of relationships to begin with. but my Nana started dating my Bapa at 18 when he was 28 and they were together until his death. i think it just depends on the people involved.
But at 18 a girl is an adult, and should be matured enough to know the difference between somethings.
iuno, just find it odd, is all.
But.. if a 23 year old guy can't get a 23 year old girl, or at least someone older than a girl who JUST turned 16, then something is wrong.
but thats just MY OPINION.