Though bitcoin or blockchain technology seems complicated especially to those younger minds, I admire your innovation to integrate this kind of technology and how this bitcoin works. If I were just by your side, I will accompany you to teach those secondary students. But i will just teach those who are willing to learn. It is hard to force them to learn something about new technologies like bitcoin.

However, continue your purpose since the Principal allowed you to do the teachings. Just make it a simple, collect some infographic and videos for them to understand it well.