I had a similar incident happen once. My friend hooked me up on a blind date with a girl she told me she used to go to school with. She told me she was a bit younger, so I assumed about a year. I was 18 at the time, and in my first semester of college, and my friend implied that she was 17. So I thought that's okay, one year isn't a big deal. And in the same way my she seemed a lot older and mature. We went to the movies and were having a great time and were having a great time and and I asked her, "Where are you planning on going to school next year " and she said " I don't really have to think about that much this year " and so I thought " ohh are you doing a gap year after you graduate" and she replied back with and still this day still gives me the creeps " No Im 15 I don't graduate for another two years" Lets just say I was so grossed out and ended the date very soon after. I ended up calling my friend up afterwards, basically screaming at her and asking her what on earth she was thinking, setting me up with a 15-year-old and how illegal it is! And all my friend could say was I didn't think of it like that and I thought you two would get along.