Gillian Jacobs was 21 in Building Girl when she played the character 'Katie'.
That was over 19 years ago in 2005.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 41, and has starred in 49 movies in total, 46 of those since Building Girl was released.
In Building Girl, I think Gillian Jacobs looks: