Starting early to pass responsability and having discussions about earning money, saving it and not spending it for nonsens. I think nowadays with smarthphone and easy to use btc wallets I would start practicing transfers quite early and motivating to build a visible own stack. We for example reduced the fiat shopping attitude by not having a TV (like my parents) and organising a very vital family life with tje fams of my bros and the others of my wife's. It's a process and You should define basic principles together as parents that help You to navigate because there will be wild things happening that You can't control easily.
Wish You a good hand on the cards!