Jannik Schümann was 14 in The Three Investigators and The Secret Of Skeleton Island when he played the character 'Justus Jonas (voice)'.
That was over 17 years ago in 2007.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 31, and has starred in 27 movies in total, 26 of those since The Three Investigators and The Secret Of Skeleton Island was released.
In The Three Investigators and The Secret Of Skeleton Island, I think Jannik Schümann looks: