children are in age where they should be away from earning process,teenagers on other hand should know about technology ,everyone nowadays is tech savy and will understand basic technology nicely so they just need to get aware of bitcoin and cryptocurrencies and other basic stuff related to it for eg-wallets,their way of working,some basic idea about blockchain and rest leave to them ,there more they learn themselves better they will be at it.
Everyone might have a smartphone but that does not mean that they are going to understand bitcoin easily. Bitcoin is a combination of principles of economy and technology. Bitcoin is a little hard to understand at first but of course there are explanations of bitcoin in layman's terms. This way, you can understand bitcoin even without having prior knowledge to it. When I don't know something, I usually just search explanation of it in layman's terms. It makes you understand better because it's using examples and analogies instead of technical words that you are not able to understand.
In the future, bitcoin will become a mainstream thing and people will know about it even if you don't force them to. They are going to learn about it by the time they are ready. No need to separate the youth from the adults, both have brains enough to learn about bitcoin.
There is a perfect book for that: "Bitcoin for Dummies". Your kids will get the entire idea easily 
Usually "for dummies" books are made my dummies themselves. Just my opinion, since I had a bad experience with these stuff.
Yeah, that's why I search "in layman's terms" instead but sometimes books for dummies are alright. Otherwise they are not going to be so rampant.