How do I tell him to leave me alone?? Hes scaring me!?

Theres this guy, hes 15 and im 13. I met him at camp, and he got my number. We were talking and he asked me how far I have gone with a guy. I said i dont wanna answer. Then he asked me how far I would go with him. So I said idk! And he said I would go all the way home with you babe. So Im like omg! He luckily lives in a diff state, but not too far from me. About an hour. He kept telling me how h*rny I was making him, and I was like uhhhh. So then he asked if I wanted to know how big he was. I said no thanks. He also asked if he sent a pic of him (if u know what i mean, i dont wanna say it) would I send one of me. And I said no, and told him of a girl that got suspended from that. Hes pretty hot, but I mean hes 15 and im 13. How do I get him to back of a little?