I really should know better

Was trying to explain 'Revenge of the Sith' to my mother today. She wanted to know if it was sad. In the course of my explanation, I mentioned "his wife" and then I had to explain who "his wife" was. It's partly my fault for forgetting what happened last time we did this.

After the Phantom Merchandiser actually. She'd been to see it as part of the school holiday program and after the rest of us had seen it, we got to explaining a couple of things for her. After a few mins, she goes "Oh, Anakin is Luke's father." Yes, his father, not his son. (Slightly revised version of movie starts to play in my head at this point...)

You see sort of see where today's conversation went, can't you?

Then his wife--
You mean his mother?
No. his wife. Anakin's wife.
Who, oh, you mean Vader?
Yes, his wife, Luke's mother.
Isn't she really old by now?

( Spoiler space )

I do love my mother but she obviously doesn't "get" Star Wars, or at least the order of the movies.