Holliday Grainger was 8 in The Missing Postman when she played the character 'Harriet'.
That was over 27 years ago in 1997.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 36, and has starred in 27 movies in total, 24 of those since The Missing Postman was released.
In The Missing Postman, I think Holliday Grainger looks: