River Phoenix was 12 in Backwards: The Riddle of Dyslexia when he played the character 'Brian Ellsworth'.
That was over 40 years ago in 1984.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
In 1993 he died aged just 23, starring in 22 films in his career, 21 of those after Backwards: The Riddle of Dyslexia was first released. If he were alive today he would be 53.
In Backwards: The Riddle of Dyslexia, I think River Phoenix looks: