Okay, I think you made a good choice if everything you heard is true. Is your friend reliable? Is it possible she's meddling, exaggerating, or doesn't know any better? I would certainly try to corroborate her claims with the girl you were planning on going out with (how subtly or explicit is up to you) before jumping to any conclusions.

It does seem like she genuinely wanted to go out with you. It just also seems (if your friend is to be believed) that her friends were really making her doubt herself and she was a bit embarrassed to admit how she actually felt. It's not unbelievable. To me, the issue is that she is embarrassed about going out with you now knowing what her friends think. You don't want to start a relationship where your partner is ashamed of you and has to hide you from her friends. Because of that I think it's a good choice not to pursue.