Balk Question

Although perhaps a general question, this pertains to our local youth rec league (i.e. not a high level of skill or experience).

Runner on 3rd only. Right handed pitcher comes to set. He sees the runner with a big lead, so he runs at him to drive him back. He does not throw.

This is the question: Does it matter which foot moves first? I’ve seen pitchers run at the base runner many times, and they always step with the non-pivot foot first. But yesterday in a game a kid stepped off with his pivot foot first. The set was good. All movement was towards 3rd base. Does the fact that he disengaged the rubber with the first movement being his pivot foot stepping towards 3rd (rather than backwards toward 2nd) make it illegal??

that would be a balk. Must step towards the base with non-pivot foot first. A lot of leeway is usually given with youth pitchers though.