They are both 17.
As of the 2014 MLB season, Kirk Nieuwenhuis is 26 years old.
Tommy Kirk is 69 years old (birthdate: December 10, 1941).
Matt Kirk is 30 years old (birthdate: June 30, 1981).
Kirk Hinrich is 36 years old (birthdate: January 2, 1981).
Kirk Muller is 45 years old (birthdate: February 8, 1966).
Justin Kirk is 48 years old (birthdate: May 28, 1969).
Kirk Saarloos is 32 years old (birthdate: May 23, 1979).
Kirk Thornton is 54 years old (birthdate: May 13, 1956).
Kirk Brandon is 55 years old (birthdate: August 3, 1956).
Kirk Broadfoot is 33 years old (birthdate: August 8, 1984).
Kirk Baily is 58 years old (birthdate: September 9, 1952).
Tara Kirk is 34 years old (birthdate: July 12, 1982).