Had a situation where the age gap was questionable when i was in school, i was sixteen and she was thirteen. Though not really the age gap but the year gap, she is was in year nine i was in first year sixth form(So it went 9-10-11-me) which some people questioned. Generally age wise there was only a 2 year and seven month gap but the gap between the our year groups is what got people talking.
She was nice, i enjoyed her company and she seemed really...horny to be blunt, suppose a good term would be "enthusiastic learner" since i was her first "real" boyfriend. We had some general things we both liked/disliked and it seemed to go well, despite the fact half the school were whispering alot and even some teachers for that matter(more though to our public displays)
Seriously was the best two month relationship i had, she was rather agressive in the making out parts(let's say she was forward anyway) and i can't deny she was awesome in that respect. Although having stares and whatnot were ennoying from time to time from students and teachers it was worth it to see my previous economics teacher walk past us one day as say "keep it up" with a wink. Ended it though when i found she was a self harmer and went to a psycologist, was not in the mood for that kind of bagage(though i'm sure i did not help by dumping her)
It does get creepy i can say though at 19 years old to go out with females younger than you, i mean 19/17 year old seems normal, 19/16 would be a fine line to generally draw myself(as it does sound creepy unless the older partner aint actually a sleeze) any younger and i'd avoid it like crack.
It's hard to meet osmeone younger(14-16) and fine a real connection when your the older party.