Dude, just go to her party, it sounds like a good time. You have to think about having fun too, what else is life for

Whether you want to go Friday or Saturday, that's your call. Saturday will mean more targets, Friday will mean more intimacy. So really it's your call, both options have their advantages.
Though do make sure she's not a guy or a tranny, this is craiglist after all. Or that she's not trying to get you to come over to her place where her team of highly trained surgeons will divest you of your organs.