Why was annemarie surprised by uncle henrik's announcement that there was to be a funeral?

I believe the answer is: This was the first she had heard of a death in the family and no one seemed sad.

Beside the fact that no one seemed said, what concerns Annemarie is that she also had a good memories of the family that her mother ever mentioned in her stories. And she pretty sure that There was no Great-aunt Birte. Annemarie believed that She didn't exist.