This thread reminds me of why I'd never relive my late teens and early 20s.
In response to the OP, there's a thin line between appreciation and exploitation of teens. This applies whether we're discussing a ten-month age difference and a ten-year age difference. This is because younger adults haven't gained enough experience to adequately assess the motives of those who mean harm.
It's a long, tough learning curve, and one that is made easier by keeping your romantic associations to your peers (or near-peers). FWIW, I don't think I've fucked anyone under 25 since I was about that age, too. And I can't imagine doing it now.
This is a nice, thoughtful response and reminds me of some things I haven't considered since my 20s. But I do remember that at 21, a guy 10 years older than me seemed very old.
In the end, it really does have to do with the differences in social sophistication and maturity, and your own personal feelings on the subject, rather than just the number of years between you. The years are just a guideline rather than a deciding factor. Never hurts to strike up a friendship though, couple of dates, and see where it goes. Just don't force it. If it doesn't seem right to you, there's no reason to continue it.
Oh, and by the way: If you decide you aren't suited for each other, it doesn't reflect negatively on you (or him). Don't read comments about level of maturity in this thread as a reference to some weakness. It's just a fact that people are still "growing" as adults in many ways well into their 20s or beyond.