I think we can start explain bitcoin by tell them that bitcoin is like other international currencies dollar, euro and many else. They will understand and you explain more about bitcoin.
I think its unnecessarily needed for a teen or a child to know bitcoin, at young age are you going to set the fact that wuthout money people are nothing ? Not being drastically emotional, butwhat I mean is bitcoin is too techy for a child to understand let them know it soon at their right age where in they can manage their time unlike being a kid , we should not expect them to learn everything we want them to to know and as well as theyre too young.
I agree, even now I still do not understand bitcoin fully well, maybe that explains how we are having a hard time to teach bitcoins to others as well specially with teenagers and children. You can't simplify and teach something you do not master may be the best way you can do is to spark their curiosity and attention to bitcoin and the rest will fall onto its right place. But i don't think kids will understand anyway.