What to do with a sucky friend?

You do not need to read the whole life story you can skip to the end but if you have the time then read. Lol

I knew her I think our whole lives. But she just has this personality and attitude I can’t stand. She tries to hard to be “cool” and she just isn’t so I want her to stop. If I talk to her about it (like a good friend to a friend) she gets all annoyed with me and acts like she doesn’t know what I am talking about. Also if I am talking to someone who is supposably “popular” or cute she butts into the conversation and starts acting all beachy to me. And she does that beachy talk to me when ever there are people around to impress. If I say something to her she gets pizzed of at me later for embarrassing her in front of people. I feel bad just ending the friendship since we have been for so long and I am waiting for her to act normal but it just isn’t happening. And I know she will talk sheet about me if I end it so … What do I do with this friend???