How do you deal with it? A lot of it is instant contradiction and it's incredibly frustrating and exhausting.
Latest example.
Me: Mum, do you remember the name of my maths tutor? (I actually wanted to know this)
Her: He wasn't your maths tutor , he was your economics tutor.
Me: No he wasn't, he was maths. When I stopped going I went to Mrs X, and she was my maths teacher.
Her: who was your economics tutor then?
Me: Miss Y, the blonde lady from x highschool.
Her: oh well, it's been too long I don't remember.
Me: That's fine , but why not admit that then instead of insisting he wasn't maths?
Her: I can never say anything to you! You always argue with me.
This happens a lot and unless I provide "evidence " and actually prove my side with details or whatever she's right and I'm wrong. When I show her I'm right (rarely, because unless I need an answer/information related to the topic I let it go) then I'm the bad guy and I always argue with her. And of course the eternal defence of "I don't remember".