I don't think it is needed to teach kids about bitcoin because eventually they will use it and understand bitcoin. So i think it is a waste of time trying to explain bitcoin to kids. I think that you should rather teach them some manners.

It is already to late to buy bitcoin right now because the value has been rising so fast and now it is at such a price not many people can buy a bitcoin.
So the best thing to do is probably wait for the bitcoin value to go down.