why didnt cowboys kick a FG

In the NFL, extra points and field goals >20 yards are taken for granted because the players are pros.

In pee wee, a field goal is extremely hard. Finding a kid that can kick around 20 yards is actually not the hard part. That's a misconception. The problem is:

1) the snap

It's VERY hard to find a kid who can snap the ball right to the quarterback, who is 10 yards away, consistently every time.

2) the line

It's hard to get an offensive line that can hold 11 people who all want to block the kick.

When I coached, we got #2 settled but we could never be certain about the snapping. The big challenge is that the play is extremely-reliant on the orchestration. Everyone has to do their job and do it reasonably right or the play can fail. If the snap is even slightly off course, all hell breaks loose when the holder has to fetch the ball and try to throw a pass ("fire", we called it) It's not like a normal snap, where one kid's athleticism can compensate for another's mistake. (e.g, by outrunning someone or jumping to catch a pass, etc)