HELP i need more advice!!! I (girl) think im falling for my best friend (girl) idk what to do!!! HELP!!!?

Ok im 17 and im a girl...ive always been sure i was straight but recently i think im bi...ever since i met my best friend (also a girl) about a year ago...i think im falling for her...but when i met her she said she was straight but im afraid to ask n i dont think shes gay/bi...but when its just us two we hold hands n give each other back rubs n cuddle n stuff n goof around like grab each others n s n play footsie n shes even kissed me on the forehead...but i still dont think she is. all her friends give her a bad time like call me her gf n say shes gay n stuff n she gets really pissed like it really upsets her like shes straight...but idk what to do all i can think about when im with her is making a move (i even get wet...) ...even tho im so comfortable with her n i tell her everything idk if i should tell her this or not i dont want to loose her friendship...HELP please...