Re: URGENT new years Eve advice
I think you should simply weigh out your options.
On one hand: You'll be with her for new years eve and get the kiss. Her sis likely likes you. You get a chance to show her another side to you.
On the other hand: If it's not your scene then it will work against you. She isn't coming to hang out with you, but you hanging out with her. Big power shift if this is the beginning. (Not a big deal if you have rapport.)
Last thing, depending on what kind of girl she is, she may just make out with the guy next to her at midnight if you aren't there. Who doesn't want a new years kiss? So you have to make a choice.
P.S. If you can get her to cancel her plans and make new ones in your favor that would be great. Unlikely...but great. Good luck.
"All things are subject to interpretation. Whichever interpretation prevails at a given time is a function of power and not truth."