I don't want to talk to my grandma
Why don't you want to talk to her?
You know how it is with elderly, she starts to lecture me about the hardships of old age
You should make time for older relatives. You will miss then when they are gone.
I'm going to pretend that I knew what she was talking about so she would shut up.
Even though I think that is a little mean, it's still good that you're going to spend time with her. There's nothing wrong with humoring her.