About the whole age gap thing. Yeah... I definitely do think that when the younger one is below 17/18 then an age gap of 15 years is definitely significant. An adult of 30 has experienced a lot more and the teenager usually doesn't even think about the differences in maturity. Plus a lot of young people do tend to make irrational decisions and don't even know what they're getting into when they hook up with an adult much older than them.
And then there's the fact that the adult themselves could likely be taking advantage of the age gap.
But the older they get then an age gap of a 20-year-old with a 35-year-old doesn't seem that big anymore.
Let me just one example from my own experience. I'm 26 and I have a friend who's 14. We get along perfectly fine and we can talk about our interests together. But there's a barrier. I never bring up stuff that's too personal and I told her that she also should avoid bringing up stuff that's too personal. In that way we can avoid getting too awkward because obviously our levels in maturity are big, if not massive, and I wouldn't want her to feel that she can feel completely "safe" with me nor that she can trust me with everything. I'm still the adult in the friendship and I ought to take responsibility for it. You never know when she could meet another person (a man) my age who DOES have other intentions with her and then tries to groom her. Then I would feel it's my fault for giving her an example that she can trust just about any adult trying to befriend her.
Besides this. I know that (if) the moment she starts making advances on me I will immediately have to reject them because it's just not right. Have any of you ever been (stupid) teenagers in love before? Would you ever be able to look back on it and think "yeah. It's completely right that an adult wanted to date me when I was that age"