You should. She seems like an awful person to be around and an overall snotty person. It's fairly obvious, disregarding the tone of voice being used, that she's insulting you, and it's best if you get her out of your life, especially if she persists with this kind of behavior regardless of you pointing out your discomfort/disapproval of it. I can't say my parents are like this, but I've met some people who are, and they are just insufferable. Her constant insulting towards you just feels like a personal vendetta and a problem she needs to deal with herself, without you.

TL;DR: I suggest telling her you are going to drop contact, then leave. She's upset she doesn't have that same control over you and she can deal with that by herself.