For my side its better to teach bitcoin to children in thier exact age just to avoid their attentions in study. i prefer to teach theme when he/she knows what it is all about and what is the use of it in thier future. We all now that childrens now are grewing up with a new age of technology most of theme are  updated on social media and  knows the function of  gadgets and  computers without teaching and because of that children have already knowledge on how to participate crypto because in crypto there is a bitcoin forumit is it also like a social media you just make a good post or read  the post of other member  and reply with your different opinion.