Fionnula Flanagan was 22 in Deirdre when she played an uncredited character.
That was over 59 years ago in 1965.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 82, and has starred in 67 movies in total, 67 of those since Deirdre was released.
In Deirdre, I think Fionnula Flanagan looks: