Katherine Moennig is 33 years old (birthdate: December 29, 1977).
This answer is closed to changes. This is done in rare cases when questions are being vandalized or answers have become debates. E-mail reopen @ answers.com (no spaces) if you would like it to be reopened.
Katherine Mansfield was born on October 14, 1888 and died on January 9, 1923. Katherine Mansfield would have been 34 years old at the time of death or 123 years old today.