Friend/relationship problem

I have a friend that I have mentioned before in an earlier post, we are very close recently. (P.S. We are all 16 or 17 and we are all juniors in high school). For awhile I thought that we could be more than friends but I never knew for sure if she was even gay or had those feelings. And she means a lot to me, she is the closest friend I have right now since -I kinda pushed away my BFF (we've been BFF's for almost 10 years and our families have past ties like with my oldest brother and his oldest sister were friends) because I thought that he was bad for me and I felt used, mostly as his emotional crutch (that's what my family told me). He is emotionally unstable and has been to a mental hospital I think 3 times and every time he's gone, I've been there for him but doesn't seem to be getting better at all, and even has gotten into weed and E-cigarettes. So I kinda pushed him away a little, giving him some distance, in hopes that he would fight to keep me as his friend, unfortunately he has not done much. We say hi sometimes and occasionally he asks if I want to do something (hang out) but I kinda just avoid it. They girls he has dated in past years that messed him up, he has been talking and being friends with them recently which I think is a terrible idea but he's been handling it well.- But anyway the girl I was talking about is a good friend and she is loyal but she has a defense that scares me, if she thinks you don't like her or hate her then she completely blocks you off and she acts like you don't matter to her anymore she won't let anyone see her emotional sad side, I know when she is alone then she lets it out but never around people. It's like she keeps me close but never really close, every once in a while I catch her quiet comments about how she is jelous of him if she sees us talking a little. I think it's really cute but I'm trying to get myself to not think of her in that way so we can be really good friends. We both think of eachother and our mutual friend almost bestfriends but never say it outloud. She hangs out with our mutual friend a lot and another one of her friends and they like actually go places but everytime I say we should do something like movies, our mutual friend is all for it but her anwer is alway 'I don't know, I'll ask' like she is being forced to, when we hang out it's fun but she never wants to do anything, if it's her plan or our mutual friend then it's all good but I feel like if it's mine then it's alway 'I don't know' including deciding what to eat it's always 'what ever you want'. I feel like I have to choose between him or her or atleast prioritize one over the other but I feel like one isn't good for me and emotional Yusss me to just fill up time and the other I have strong feelings for but I'm afraid of being dropped so quickly like nothing matters. If you couldn't tell, I'm extremely loyal maybe to a fault and u would feel really guilty. (Sorry for the essay, only people I could talk to are the people it's about).