I want to cut off one of my best friends
Why do you want to cut off one of your best friends?
I will have more time for important things.
Is this the only reason? It seems like it is not a good reason to do this. You can have time while also having a best friend.
She is a stuck up bitch, a terrible friend. She has no idea what's she's talking about. I don't want to be with her.
If she is doing all of these things to you, then you should cut her off. Spending time with people that treat you badly is no fun.