Friend and crush getting together?

My friend and I are both bisexual, as is this girl we both like. I m friendly with the girl but my best friend is always texting her, they re really flirty and it s obvious they re going to end up getting together at some point. I feel so stupid because I knew the girl first but I m so shy I completely ruined my chances, and my friend is really clever and confident and flirtatious with everyone How do I deal with it if they do get together? Ever since we were little everyone has always preferred my friend to me and I have such low confidence, I can t help but feel incredibly jealous and rubbish about everything.

I should also add that I'm not afraid of this ruining our friendship - I have much too low self esteem to get competitive or even show jealousy. I'm going to have to grin and bear it, like I've always done. I guess at least I can still be friends with my crush, which is a comfort of some sort because she's completely amazing.

Any advice or sympathy? I feel so alone and pathetic for even thinking I had a chance. Thank you