The Bright Side

Dee: I'm not sure it's measurable. Would we go by the universe's time, which is straightforward and all that, but is way shorter than my actual age, or would we go by my personal time including all the backtracking I do? Because I have no idea how to measure that.
Emily: Hm... I don't know. Universe time, I suppose. So, what's your birthday in Earth time? What's the anniversary of you popping into existence?
Dee: Eh, who cares. I'm inconceivably old, let's leave it at that.
Emily: I'm not asking your age, I'm asking your birthday!
Dee: Why?
Emily: Because! I want to know when it is! I was thinking about stuff like the Mexican Day of the Dead, but then I figured that probably doesn't have a lot to do with you personally, and anyway this isn't Mexico, and...
Dee: Why, though?
Emily: Because. I have a birthday. It's recognised. People celebrate it. It seems only fair...
Dee: Yeah but you're mortal.
Emily: So!?
Dee: There's no point to birthdays when you're immortal.
(Skateboard boy from page 179 and his friend are on the other side of the street.)
Skateboard boy (yelling): HEY! Who are you talking to!?
Emily: I don't know but it's not you!
----
Alt text: he doesn't want to admit whether he first turned up on Earth or some other place