Carrie Fisher was 12 in Debbie Reynolds and the Sound of Children when she played the character 'Girl Scout'.
That was over 54 years ago in 1969.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
In 2016 she died aged just 60, starring in 97 films in her career, 94 of those after Debbie Reynolds and the Sound of Children was first released. If she were alive today she would be 67.
In Debbie Reynolds and the Sound of Children, I think Carrie Fisher looks: