Exactly this. I am a teacher, and I always tell my students “There is no such thing as a stupid question as long as it seeks to clarify, or to deepen one’s understanding. Any question posed with the sincere desire to better understand something is welcome.”

There are students who will ask questions because they weren’t attentively listening to my explanation (their peers always say something like “He just explained that”) — I will patiently explain it to them again while the rest of the class listens in (or tunes me out because the were listening and don’t need or want to hear it again.)

I want to encourage them to ask questions whenever and where ever they encounter things they do not understand; I hope that this mindset encourages them to do so whether be at school, at work, or in their personal relationships.

Best answer so far, but I think it discounts one small but important thing, so I would like to elaborate on it. In a time when the scientific method itself is being thrown into distrust, how is a reasonable young person supposed to determine who they can trust to be truthful?

You can't expect them to personally repeat the entire history of science experiments to verify the findings for themselves.

They do have one potential solution though, they can ask us. They can then watch us hash the answer out amongst ourselves, using the internets naturally argumentative nature to their advantage. They can directly question particular answerers, to unearth more detail that pertains specifically to what they are trying to understand.

This is all actually a pretty intelligent strategy, and I think it highlights the importance of spaces specifically like this one. It's why I participate in them fairly actively, as my own internet debate chops are very, very thoroughly practiced, and that can actually be useful to others.