I'm soon to be 19 next month and I know where you're coming from. Most of my friends, all of the six save one, have moved on to college or something else.
Enter Sid and Kati. Long-standing boyfriend/girlfriend duo from way back in middle school. I don't suppose it's wrong to say that they behave like a brother and sister who operate in tandem with each other in every-day life. They're both officially bisexual.
I think you can see where I'm going with this. Both Sid and Kati are 14 or 15. They honestly remind me a whole lot of how I was when I was their age. I love hanging out with them, and it's no joke that because of my age I act as a sort of wizened and experienced operative to them. I tell them all sorts of stuff, from programming languages to pot smoking to sex-ed.
What's really neat is that Kati's is a gigantic loli. She's been taking hormonal birth control for a while now, so her breasts have started to bud, but nothing more. I also failed to say that she's five foot six and i'm six foot one. She's tiny compared to me.
Anyway, the thrust of my entry here is to say that I prefer kids younger than myself, and would certainly date them or find a mate in one.
Still no help for you with the nature-nurture argument, my father is about thirteen years older than my mother. So if I marry a girl that's thirteen years younger than myself, she'd be about five years old right now. Loli city.
Having a desire for girls younger than yourself is a perfectly natural thing. It only really becomes pedophilia in my book if the loli in question doesn't want anything to do with you.