I disagree. I'd say having all of the work in 1 commit makes it more likely to have been created by a young programmer. What impresses me the most, and makes me skeptical, is the good code style. I know at least 3 12 year old programmers who might be able to do this, but none of them have this diligence for style.

The program is short enough and I was enough of a nerd at this age to be interested in doing something like this. I just focused on making poorly-designed computer games instead.