Milo Ventimiglia was 17 in Must Be the Music when he played the character 'Jason'.
That was over 28 years ago in 1996.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 46, and has starred in 35 movies in total, 33 of those since Must Be the Music was released.
In Must Be the Music, I think Milo Ventimiglia looks: