Kate del Castillo was 4 in Los de abajo when she played an uncredited character.
That was over 46 years ago in 1977.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 51, and has starred in 31 movies in total, 29 of those since Los de abajo was released.
In Los de abajo, I think Kate del Castillo looks: