Sarah Polley was 5 in One Magic Christmas when she played the character 'Molly Monaghan'.
That was over 38 years ago in 1985.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 45, and has starred in 49 movies in total, 48 of those since One Magic Christmas was released.
In One Magic Christmas, I think Sarah Polley looks: