- You sure you're just 12?
- 13 next summer.

5 seconds sound clip from the Batman & Mr. Freeze: SubZero movie soundboard.

You can hear this line at 00:40:44 in the Blu-ray version of the movie.

Quote context

[...]

- My name is Koonak.

- You're just a kid. What are you doing here? Did Freeze kidnap you, too?

- No. And I'm not just a kid. I'm 12.

- 12, huh? And very handsome.

- You're kind of cute, too, lady.

- You sure you're just 12?

- 13 next summer.

- So where are your parents, Koonak?

- They're dead.

- Oh, I'm sorry.

- But Mr. Freeze takes care of me now.

- Freeze? You got to be kidding.

[...]