Glasses?

Thing One: Is I'm going to have glasses when I grow up?
Me: Probably.
Thing One: Because Grandpa didn't have glasses when he was a little boy and then he got glasses when he was bigger.
Me: That's right. How did you know that? Did he tell you?
Thing One: I saw pictures of him when he was a boy and he didn't have glasses. (on the photo boards at Great-Grandpa's funeral)