Any advice for a guy emotionally stuck between two girls?

So yeah, I basically mentally and emotionally got myelf stuck between two girls. I feel so dumb.

Girl A is a close friend for whom I fell for and been rejected (hate using that word) by twice. First time wasn't so bad, but the second time broke me big time for a couple months. We got passed it all, I got over the hurt/my inner bitching, and are still good friends. We hang out often for which I'm glad. Also, I promised myself not to fall for her a third time out of fear that we'll lose each other as friends. So far so good, BUT... there's another girl; let's just call her Girl B.

Anyway, I'm interested in Girl B. We have done light flirting, engaged in dorky conversation. It has really helped build my confidence and I'm really wanting to ask her out. I'm not worried about being rejected, if anything I'm totally prepared for that. I'm just a little worried that (A), my friend might get jealous and start liking me right when I'm ready to move on. Especially since she's who I want to ask for advice. You see how things could get muddled. And another thing: I'm down to be with her if she changes her mind/things don't work out with Girl B, but I'm not gonna wait for her. Feelings are just so taxing, hard, and confusing. I'm sure you all can understand. Or (B), we could just drift apart all together.

I know I'm clearly over-thinking this whole "situation", but I can't help it, it's just in my oh so annoyingly cautious nature. So, any advice to help ease a late bloomer trying to figure things out would be very much appreciated.

Many thanks.
Any advice for a guy emotionally stuck between two girls?
Add Opinion