Should we just be friends?

okay well my neighbor for about five years now i'm starting to like.we used to hangout all the time but stopped for a while and now we hangout a lot again. a few months ago i introduced my best friend to him and she had no interest at all in him but they went to prom together and kind of did stuff after but it was kind of just like a whatever thing i guess and she said she didn't like him. now me and him have been talking and we hung out last week and we both like eachother. we were in his car and he put his hand on my leg and stuff and my best friend saw and she got all mad. she keeps saying every guy always ends up liking me and is really mad that we are talking when i have known him years before her! alsooo she really really likes this other boy and they talk 24/7 and hangout a lot and will probbaly go out soon. soooo i don't know if i should talk to my neighbor more or stop and just be friends because of my best friend! heellllppp!