No need for teaching. Why set an age where should they learn? Preparation? That was crazy. It's not something that you need to prepare for 10 years lol.
Just watch them grow and let them encounter the things without us interfering with them. Trading is important but we should not force them to undergo trading without their interest in it. Soon, they will encounter it and will ask for help. That's the time we need to step in.
Basically if we force something to learn it I don't think it will last long,
let them explore their own interests i think it's much better and when he is interested in learning the trade that's where we teach him,
I think it's much simpler and wiser