J.K. Rowling was 34 in The Magical World of Harry Potter: The Unauthorized Story of J.K. Rowling when she played the character 'Herself'.
That was over 24 years ago in 2000.
This was her first recorded movie acting credit (although may not technically be her first actual acting role).
Today she is 58, and has starred in 13 movies in total, 12 of those since The Magical World of Harry Potter: The Unauthorized Story of J.K. Rowling was released.
In The Magical World of Harry Potter: The Unauthorized Story of J.K. Rowling, I think J.K. Rowling looks: