When your boyfriend wants to get serious and acts strangely as if he owns you, and you don't want that, what would you do?

Actually, I’m a 17 year old girl and 2 months ago I got into a relationship with a 20 year old. I have to admit that he’s pretty gentle and he shows me his affection everyday, but he says he wants a serious relationship, at the beginning I just ok “ok, let’s try” but I can’t say I really like it. For example I had a very close male friend and every time I hung out with him, my bf got really mad by saying that now that we are together he should understand that I can’t hang out with my friends as I did before. I said I could try and decrease a bit the time I spent with them. But he gets really mad even if I dedicate a Friday with my mates… Plus he says that when I graduate (he knows I want to study and live abroad) we could have a long distance relationship and he tries to convince me to live here in Greece… I really wanna talk about it and at this point I really don’t mind breaking up… I mean I’m a 17 year old girl and I wanna live my life properly… But the problem is one of my friends (best) from my previous school likes him a lot and tells me not to break up, as he loves me ect… I’m desperate right now… Please help me :( Thanks :)