Katie Cassidy was 18 in When a Stranger Calls when she played the character 'Tiffany Madison'.
That was over 18 years ago in 2006.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 37, and has starred in 19 movies in total, 18 of those since When a Stranger Calls was released.
In When a Stranger Calls, I think Katie Cassidy looks: