Just let them watch while you do your thing on bitcoin. and maybe let them post some things and let them see how fast bitcoin is growing and how much difference there is in bitcoin a few years ago and now.
That can be a good idea for us on teaching or explaining bitcoin to teenagers because it will help them to fully understand the process that they need to obey in order to have a good way of making a good work in bitcoin. Keep them watching and if there is a question from them then it will be easier to ask since you will explain and demo it in person.