Confused about feelings, should I do fwb with him if I am a virgin?

Hello guys, I’m 21 y.o girl, who is at this moment a little bit confused. Well I’m still a virgin, but from some time I feel ready, but as you can guess – I never wanted to do it with some random guy. I had some occasions to ”get rid of it”, but never felt that this is the guy I want to do it with, just did not felt that comfortable with them. Well some months ago there appeared one guy well who I thought could be my first one. Yes I thought, but now I’m not really sure. He was really interested in me at first, but I wanted to take things slow, and told him that I don’t like rush for anything and I’m just not sure, well after some time then he just moved on. And I get this, but I mean it wasn’t that long time, and I thought he really liked me, then why change his decision that fast? We are pretty close, he knows my situation and we have done some stuff together, but not sex. We still talk a lot, and he says he cares about me but now like a … friend. And I just don’t get it, how I became that fast just a friend for him. When I asked if there is some girl who he likes he said no, and that he don’t have relationship like ours with anybody else. Was it a lie? I have no idea. Now are are at that place when we are those friends but we flirt a lot, and talk about sex. So well now I think I catched some feelings… they are not that deep, it’s not like I’m sure I want to be with him, but I would just like to know that there can be something from it, and I just can’t accept that he moved on that fast. I am thinking things like if he do this on purpose because he knows I must go know person first better, and also that I tend to catch feelings when someone is more distant… he knows all that and I’m not sure if he doesn’t play now with be – but for what? Just to get laid, or maybe he cares more than he says? And the last things, I don’t know if I want to do it with him, because if this will be really just fwb for him I’m not sure I could control those feelings and if they will go away, but I’m really curious and ready, and I just don’t know when I will feel comfortable with someone again… what would you do in this situation? Sorry for messy story but I was just writing that what was on my mind