Bill Skarsgård was 8 in White Water Fury when he played the character 'Klasse'.
That was over 23 years ago in 2000.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 32, and has starred in 39 movies in total, 33 of those since White Water Fury was released.
In White Water Fury, I think Bill Skarsgård looks: