Kevin Smith was 20 in Mae Day: The Crumbling of a Documentary when he played the character 'Self'.
That was over 32 years ago in 1992.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 53, and has starred in 113 movies in total, 111 of those since Mae Day: The Crumbling of a Documentary was released.
In Mae Day: The Crumbling of a Documentary, I think Kevin Smith looks: