Jennifer Aniston was 18 in Mac and Me when she played the character 'Dancer in McDonald's (uncredited)'.
That was over 35 years ago in 1988.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 54, and has starred in 56 movies in total, 51 of those since Mac and Me was released.
In Mac and Me, I think Jennifer Aniston looks: