Finn Wolfhard was 9 in Aftermath when he played the character 'Young Charles'.
That was over 11 years ago in 2013.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 21, and has starred in 20 movies in total, 17 of those since Aftermath was released.
In Aftermath, I think Finn Wolfhard looks: