Summary: Twelve takes exception to being called old.
“Aren’t you a bit old to be running around like this?”
The Doctor supposes that’s what comes of taking a mere child on a trip. He’s not sure how old this one is, but he can’t be more than twenty or thirty. He’s still in school, probably doesn’t know any better. Not that the Doctor feels any less insulted.
“Old? I’ll have you know I’m barely a thousand, still in my prime! Don’t let the hair fool you, regeneration’s always a lottery, never know what I’ll end up with. What about you? Aren’t you a bit young?”