Stefania Sandrelli was 13 in Gioventù di notte when she played an uncredited character.
That was over 63 years ago in 1961.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 78, and has starred in 119 movies in total, 117 of those since Gioventù di notte was released.
In Gioventù di notte, I think Stefania Sandrelli looks: