Margot Robbie was 17 in Vigilante when she played the character 'Cassandra'.
That was over 15 years ago in 2008.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 33, and has starred in 41 movies in total, 32 of those since Vigilante was released.
In Vigilante, I think Margot Robbie looks: