Iain Armitage was 5 in Iain Goes Inside the Last Ship when he played the character 'Self'.
That was over 9 years ago in 2014.
This was his first recorded movie acting credit (although may not technically be his first actual acting role).
Today he is 15, and has starred in 8 movies in total, 7 of those since Iain Goes Inside the Last Ship was released.
In Iain Goes Inside the Last Ship, I think Iain Armitage looks: