Oakes Fegley was 5 in Glass when he played the character 'Boy'.
That was over 13 years ago in 2011.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 19, and has starred in 14 movies in total, 11 of those since Glass was released.
In Glass, I think Oakes Fegley looks: