Me with 7-year old.
7-year old: "How old are you?"
Me: "I'm 35".
7-year old: "Gosh, I thought you were much younger."
Me: "Yes, most people think I'm younger than I am. Do you know why that is?"
7-year old: "No."
Me: "It's because I've got autism. Most autistic people look younger than their actual age."
7-year old. "Oh. I thought it was because you wear loads of make-up."
Me, looking incredulous: "I'm not wearing any make-up!"