Does he really like me or just want to get in my pants?

There's this guy who is in one of my classes. I am 15 and he is 17. He talks to me everyday and finds random topics just to talk to me. We flirt, and he teases me, gives me eye contact when we talk, and pays attention to me. Whenever I am talking to other guys he seems a little jealous. Also one of his friends told him I am his girlfriend and he just looked down, blushed and smiled. Now this guy he talks to me about sex. Like on Friday he was telling me that I had to keep myself protected because "we" didn't want anything bad to happen. And he was talking about sucking ***** and I told him I don't do that and he stayed silent. Then he started talking back about being protected. During past conversations he has mention to me how I have a "good body" and one time he asked me if I could give him a back massage and how if I could touch his muscles. Does he really like me or just want to get in my pants?