Popping the Cherry and That's it!

So I was talking to my guy best friend, who is not a virgin, and I told him that I am over being a virgin (completely true), I'm almost 18 and I'm so ready and I'm eager to make up for lost time! The conversation progressed to the point where I asked him if he would be comfortable with having sex with me, he said that it would be weird but he would! I want this to be a good experience, I'm not worried about our relationship at all, I'm worried about him being weird about having sex 2 minutes into it and be done!