Seth MacFarlane was 20 in The Life of Larry when he played the character 'Seth MacFarlane / Larry Cummings / Steve / Lois Cu'.
That was over 29 years ago in 1995.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 50, and has starred in 40 movies in total, 39 of those since The Life of Larry was released.
In The Life of Larry, I think Seth MacFarlane looks: