Christina Applegate was 8 in Beatlemania when she played an uncredited character.
That was over 43 years ago in 1981.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 52, and has starred in 50 movies in total, 49 of those since Beatlemania was released.
In Beatlemania, I think Christina Applegate looks: