If we want to teach knowledge about bitcoin and crypto to our children, at least they are over 10 years old because if they are still too young, they do not understand the risks of investing in crypto, because the crypto market is very volatile. This is very risky if their age is not enough to understand the risks.
And this is where we actually need to pay much detailed attention to what a child learn. Should we introduce Bitcoin to a child as p2p technology, or as an investment?. Ideally, the first thing a child should know is that Bitcoin can serve the same purpose as fiat money (i.e, a child should understand that Bitcoin can be spent on goods and services).
I am not ignoring the investment and profitability aspects of Bitcoin, but if a child is introduced to Bitcoin primarily as an investment, there could be complications down the line, such as a loss of interest. A child needs to learn about things that are more relevant to their everyday life, such as buying groceries from a store.
IMO, it is very important that we take a cautious approach in teaching, because what they learn matters a lot.