He's obviously quite a bit older than you, considering how fast people grow up during teenage years. He may be wanting different things from a relationship to what you want. It's probably a good idea to talk things over with him first and not just run into anything. If you're feeling really strongly about this, just go with your gut feeling.
I'm not sure of the legal technicalities in the USA, so you probably shouldn't take my advice if you're basing your decision partially on that. I don't know the sexual consent age but there's only about two years between you, so I don't see a problem if you decided to do that.