I like a guy who is 16, and I'm 13, what should I do?

I don't look my age. I'm tall, and I'm physically more mature than girls my age. There's this guy that I really like and he's 16. I'm 13. I think he likes me, because he tried to kiss while at his yacht party on Memorial Day. We are always flirting with each other and I think it's starting to lead to something more. I don't want my reputation (sp?) trashed, but I really, really like this guy. He's in 11th grade, and I'm in 8th and we're always going to go to seperate schools. I'm pretty sure he knows how old I am. What should I do?