Date of birth
We cannot yet be sure of her date of birth.  The Vanity Fair article confirms it was in 1954, and the Heidi Evans "Eager Judi left coal town in dust" New York Daily News article says her marriage on December 8, 1974 was "One week shy of her 20th birthday," but that "one week" may not be an exact measure.  So on or about December 15, 1954 is what we have.