So you're XX now... look at the bright side, if that were dog years, you'd be dead already.

What's causing the excitement?
What's causing all the fun?
A special boy/girl is XX today.
And you're that lucky one!

Wow, you're already XX. It seems like it was just yesterday you were sitting on the couch all day, playing video games, watching cartoons, and picking your nose. Oh, wait, that was yesterday.

Enjoy this day, you only turn XX once.

You're not XX years old, you're xx years young.

Happy XX anniversary of your birth.

You look too young to be XX.

Woah! XX already? Happy Birthday!