If you mean Dirk Nowitzki... he's 33.
As of the 2014 MLB season, Kirk Nieuwenhuis is 26 years old.
Tommy Kirk is 69 years old (birthdate: December 10, 1941).
Kirk Muller is 45 years old (birthdate: February 8, 1966).
Kirk Hinrich is 36 years old (birthdate: January 2, 1981).
Kirk Saarloos is 32 years old (birthdate: May 23, 1979).
Justin Kirk is 48 years old (birthdate: May 28, 1969).
Kirk Rueter is 40 years old (birthdate: December 1, 1970).
Brett Kirk is 34 years old (birthdate: October 25, 1976).
Tara Kirk is 34 years old (birthdate: July 12, 1982).
Kirk Baily is 58 years old (birthdate: September 9, 1952).
Kirk Broadfoot is 33 years old (birthdate: August 8, 1984).
Matt Kirk is 30 years old (birthdate: June 30, 1981).