[2.0] regex question

[Pirate]

How would you go about doing this using regex :

I want to validate "Age" field which complies to these rules:
1.doesn't accept "zero" at the beginning.
2.doesn't excced 3 digits.
3.accept 2 or 3 digits.

examples of valid ages: 20 , 38,102

Sorry , can't construct this little regex string

Thank u for any help !