Annette O'Toole was 20 in The Girl Most Likely to... when she played an uncredited character.
That was over 49 years ago in 1973.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 70, and has starred in 48 movies in total, 48 of those since The Girl Most Likely to... was released.
In The Girl Most Likely to..., I think Annette O'Toole looks: