She will feel your insecurity and jealous feelings, no matter how hard you try to hide them. And they will slowly drive her away from you.

So apparently she has friends and she, or they, don't want to include you, for whatever reasons. Telling her she cannot be with those friends, that will drive her away. She has to be able to have her own life, free from you. And if to her that means having friends you can never hang out with, then the moment you try to change her position on her, it will cost you.

Better hang out with friends of your own on New Years' eve and catch up by doing other stuff together later.

If she finds her friends more important than her BF, and you feel like that ought to be different, you two maybe aren't compatible. You cannot change her view on this by talking about it.