Fuck her friends. Their opinion is meaningless.

You can't treat her like a gf when she's not your gf.
Maybe the reason why she says she's not prepared to a relationship (which isn't true. Single girls, unless they're virgins, always want to fuck guys they're attracted to. From there to relationship is just a question of how many fucking you two have and a couple of dates) is because you're treating her like you're in one and she feels it, so she resents you, because there was no seduction. She has you where she wants and you're being manipulated by her friends.

Always think for yourself and act based on your thinking, not on your feelings (unless you feel like you should kiss her). And stop treating her like a lady. Treat her like a "whore". As in, be bold, outcome dependent and don't care about what she says or thinks. If she says something bitchy, say "another one of that and I'll slap your ass" with a smirk.