BFF troubles

Okay so I have a best friend that is a guy. We have been best friends since 8th grade and for 4 years. Recently I have started to develop feeling for him. But we have talked about dating and he said that we probably shouldn't. But i'm super confused because over the summer he was talking about friends with benefits and asking if I would do it with him. I have told him I liked him and he told me back in 8th grade that he liked me. But now he says I lost my chance. Should I fight for him? Maybe go places together to maybe find something? Or should I just give up and find someone new, keeping him as my best friend?