I never asked a question once in school. In the beginning I knew everything or understood it the first time it was explained. Later I had faith that if I didn't understand the first explanation, that other students would ask the questions I needed, and they always did ... until college.
By that time I couldn't bring myself to raise my hand and admit that I was confused, and I didn't want to slow the other students down the way my learning had been slowed for so many years. I really made things a lot harder on myself than they needed to be.
I hope to prevent my children from falling into such a trap, even if I have to convince them to ask questions they already know the answers to... just for practice. Of course, the issue may not come up if they are grouped with intellectual peers from an early age, with instruction at an appropriate level.