Lois Maxwell was 18 in A Matter of Life and Death when she played the character 'Actress (uncredited)'.
That was over 77 years ago in 1946.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
In 2007 she died aged 80, starring in 60 films in her career, 59 of those after A Matter of Life and Death was first released. If she were alive today she would be 97.
In A Matter of Life and Death, I think Lois Maxwell looks: