 Menzies was a graduate of John Burroughs High School in Burbank, California, in 1967, and she studied at Falcon Studio's University of the Arts.Menzies' first appearance on-screen was in 1964, when she appeared in the TV series "The Farmer's Daughter".She was cast in "The Sound of Music" as Louisa, the third-oldest of the von Trapp children, at age 14, with no prior acting experience.