Julia Roberts was 18 in Firehouse when she played the character 'Babs (uncredited)'.
That was over 37 years ago in 1987.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 56, and has starred in 73 movies in total, 69 of those since Firehouse was released.
In Firehouse, I think Julia Roberts looks: