Bitcoin is difficult to explain. I also felt difficulties in understanding bitcoin for the firs time. Let's share how to explain bitcoin to children of teenagers. In My country I can say 98% children don't know bitcoin. In fact, bitcoin can be future money. If the children not familiar with cryptocurrency or bitcoin, how can they face the digital era in the future.
It's hard, but really you only need to taught them the basics and its all to them if they will get interested in Bitcoin. Expect that mostly teenagers that came from wealthy family will not going to have interest in Bitcoin just so easily, most of teenagers will get interested will be teenagers that came from poor or not so wealthy family.