Kit Connor was 8 in An Adventure in Space and Time when he played the character 'Charlie (uncredited)'.
That was over 10 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 20, and has starred in 11 movies in total, 9 of those since An Adventure in Space and Time was released.
In An Adventure in Space and Time, I think Kit Connor looks: