What should I do? =/

Well, there's this boy that is one year older than me. He went to the same school as me and I met him last year when I was in 7th grade and he was in 8th grade. I never really liked him, he just talked to me and consulted me for help, since he liked my best friend. A lot. But she didn't like him back. So anyways, he graduated, and then I did, and a whole year has ped since I've seen him. He only randomly IMs me on AIM, but there isn't much to talk about. Yesterday, he IMed me asking me if I wanna hang out, and told me that he likes me. Whoah. I didn't really expect this, and thankfully, he signed off a few minutes after asking me xD I don't think I'm ready for a boyfriend yet, and if I am, I don't really like him =/ What do I do, the next time he IMs me?