Gene Tierney was 18 in The Return of Frank James when she played the character 'Eleanor Stone'.
That was over 84 years ago in 1940.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
In 1991 she died aged 71, starring in 44 films in her career, 43 of those after The Return of Frank James was first released. If she were alive today she would be 103.
In The Return of Frank James, I think Gene Tierney looks: