Really casually ask if he has plans on a weekend night, and if he doesn't you should be all: "Hey me neither! We should hangout, go see a movie or something so we're not alone **that night**" :)
It'd seem casual and then you open up a whole dating world. And if he's all: "Are you asking me out?" you could be all: "Maybe. *sly smile*" And it'd be super cute :)
But hey, I'm just a loser 16 year old who obsesses over things like this. :)
As you're both consenting adults, I say you should go for a relationship with him. If you two get along really well, then I don't see the problem, unless he doesn't feel the same way for you. But if it's also mutual flirting, hopefully he does.
I agree with Join the Masquerade. I know a lot of people who have dated people quite a few years older or younger. I don't think it matters much, really. Feelings are feelings no matter what age.