All grown up

"Have you locked the back door?" asked Dad as we got ready to set off for his GP appointment.
"Yes," I said, "I've been running a home for a long time now, you know."
"Oh yes," he said apologetically. "It's just that when you're here, I forget you're grown up. I think you're still at school."
Still trying to work out whether to take that as a compliment or not...