So my Mom will be here visiting soon

A lot of feelings seem to creep up on me when she's here . None of them good . She's getting older and I see her physically and cognitively declining. She is a narcissist. I have mixed feelings about her ..our relationship has always been complicated because of my upbringing. I'm trying to keep myself in check ...it's not worth taking the bait ...it's not worth getting upset anymore ...I need to deflect and tell her that we won't be discussing certain things .