In 1957, she was chosen "Princess of the Carnival" in Hermosillo. Shortly afterwards, she began modeling. In 1960, she began her acting career, which continues to this day. Her most widely known role is that of Elita in Sam Peckinpah's Bring Me the Head of Alfredo Garcia. She also wrote the song, "Bennie's Song", which appears in the film. She was subsequently photographed nude for the July 1974 issue of Playboy magazine.
In the 1980s, Vega made her debut behind the camera by writing, producing and directing a number of films.
She was called to sing the songs "Amanecí en tus brazos" and "El Siete Mares" in the 1986 film Gringo mojado.