Please don't, I can't urge you enough to say no and to wait as you are not ready. As the others have said, he can't insist and please don't let him pressurise you. If he's worth it he will wait, if he doesn't wait and threatens to end it with you, then you are better rid he doesn't really care about you and you'll go on to meet that someone special.
Just remember, you can never have your first time again and it needs to feel right and be special, not because you feel you have to. You'll know when It's the right time and when it's with the right person, as you won't even question it and it will feel so right and so natural.
You obviously respect your body and want it to be something special with someone who loves you, so just stay true to who you are and tell him you are not ready. Good luck