First you have to ask yourself do you like the boy? And I hope he's not 40 and living in his parents basement, I'm assuming your both teenagers in high school. If you like him and want to keep seeing him then I think you need to make it clear that the idea of sex right now repulses you and that you think any girl who is having sex this early is a slut. One of two things will happen, either he will respect your wishes and maybe when you are ready you can give him that gift. Alternatively you will see his real character and he will either leave you or keep trying to get it, at that time you turn tail and run. If you decide to go over there you bring mace with you and if he tries anything that makes you feel uncomfortable or you tell him to stop and he doesn't, make sure he never forgets what the term "no means no" stands for.
Oh and if you aren't comfortable having this conversation with him, you really don't need to be with him, because people who you really match up well with you would be able to have this talk with out any hesitation.
There are three things when you get older you will regret more than anything, having sex to early, starting to curse, and beginning to drink alcohol. Save the sex for someone you really care about.