Depends on how old you are? There's so many variables. But 4 weeks or 4 dates is too early to hang with her chick friends. Like whomever said, she's gonna try and seek approval of friends and that's the worst because they have the final say. She can jettison you asap before any sex, I'd pass and reschedule. Tell her something came up and you can't go. If she's understanding, reschedule. If she turns into a rage monster, bail immediately
Here's when you know you've got her. At my girls house and I absolutely hate her roommate. She tells me her latest story and I flat out tell her she's crazy. She's fights me awhile, and I show her the evidence and she agrees. She says she needs to get a new apartment because she's super annoying and blah blah.