Can you give her a chance to change? I mean don't necessarily expect change all at once. (It drives me nuts when I'm in the process of changing and people expect me to be completely different in that aspect all of a sudden.)

I mean she might need some guidance. If she starts to complain, could you gently ask her to talk about something else? Its ok for you to tell her that you can't handle certain topics.

Could you try boundary setting with her? Like----I can't handle it when you talk about XYZ so if you start talking about that, I will not engage in the conversation (or you will walk away for a few minutes, etc).