i have feelings for my best friend of 3 years but i’m going to die a virgin so i’m not going to say anything

i’m 100% certain she’s out of my league and i’m not sure if she’s even into dudes, she’s messed around with a girl before and had mentioned being queer, but i’m the only guy she’s been completely intimate with. i don’t know what to say to her because i’m so nervous and it’s just really hard to bare feelings to a good friend because you risk losing them as a friend. um what do i do?