I'm not sure what I should be thinking?

So I'm 17 junior in highschool and I have vey strong feelings for one of my best (girl) friends we are incredibly close and are together alot but she has a boyfriend and we've had the relationship conversation idk how many times and she's pretty much hung up on her current boyfriend and that she doesn't want to lose my friendship. I do see her as an important part of my life The thing is that I'm starting to see other girls that I'm interested in but I can't help but feel that I'm holding back because I care so much for my friend Like there's this one girl who I'm really starting to like but I wonder if I start to date her would it make my friend jealous and will it start problems with all of us