I prefer older women myself, mostly because of the levels of maturity. And by maturity I'm not talking about being unimpressed or acting like an "adult". I mean not blowing up small things into big deals in order to get some sort of fix of soap-opera Twilight drama.
I like how younger girls look, and I like that I don't have to worry as much about being "man enough" for them, since "I'm older and more experienced." But then again, it's usually the young girls who think that a "bad boy" is a real man.
What you're talking about, though, is a year. A single year. You're basically the same age, even if it doesn't seem like it now. I don't think he'll care about you being older, so long as you show that it doesn't matter to YOU.
And maybe that's the reason for all of this. Maybe the reason high school guys are intimidated by older girls is because older girls would probably take a younger guy less seriously. It would be harder to impress her, especially with some of the B.S. high school standards. That's how I saw it, anyway. I figured they wouldn't take me seriously, and I would have to keep running in circles and putting on an act to keep them impressed, and I would rather just be able to be myself and have that be enough.