Family anxiety

My bf and his family have different views when it comes to politics and religion than my family does. I've had conversations about it with my parents and we are currently at a good place about it.

My younger sister moved to a different state last year and has not been back to visit. I'm currently living with my parents and they really want her to come. She would stay here at the house.

My sister is even more opposite of how my bf's family is. Everything is black and white for her. Last year was the last time I really talked to her. She FaceTimed me at work and I told her that I was having a hard time living with my bf's family because of their differences.

She told me that she would never be able to accept them because of their differences. She has picked fights with others before, people in our family, during holidays, about things she didn't agree with. I didn't tell her that my bf also had some of those same beliefs, but hearing her say that she would never be able to accept them was hard for me. I left work practically in tears that day but I never told her how much what she said hurt.

I have a lot of anxiety about her because I'm always afraid she's going to say something rude or inconsiderate to me, which she has done before, or that she'll bring something up that's a sensitive topic for me. I'd rather not have the negativity. My mom doesn't see how anxious it makes me that she is coming and she really wants me to be here when she comes. It'll only be for a few days so I'm going to have to suck it up, but my parents don't know what she said to me or how she's treated me over the years. My mom thinks it's some superficial thing, like just a little sibling conflict, but it's a real issue for me, and it goes pretty deep.