If your children actually see how you use and how you really make profit on bitcoin and they always heard a lot of times,they will eventually listen and become curious about bitcoin,that will be the right time to discuss them all about bitcoin..
Teenagers nowadays are not so much interested with profits, they want money to spend for whatever they want to enjoy their life but most probably they do not want to spend too much effort to get that, in other words they are just too dependent with there parents.
Although there are exemption as some teenager are pretty well train by their parents when they were just a kid but mostly teenager just love to spend but does not love earn.