Dean Cain was 8 in Elmer when he played an uncredited character.
That was over 48 years ago in 1976.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 57, and has starred in 143 movies in total, 139 of those since Elmer was released.
In Elmer, I think Dean Cain looks: