I have taught/did presentations for undergrad and professional level. Why? Is there a problem?
Blockchain and Bitcoin is a pretty interesting topic in financial technology, so it should be okay for the high school level.
I have done so; not a difficult topic to explore too...
I did a presentation in my class, most people liked it too...
If it's blockchain in general, I think it would be tough for audience to digest especially if they are not that knowledgeble with cryptos in general as well as the terms being used. It would be really interesting in class given the popularity Bitcoin and Blockchain is having at this moment.
I haven't experienced sharing my knowledge in front of many people but I have tried explaining it to my friends. It is a bit tough because the choice of words should be easy for them to understand. Since it is a broad topic, I tried forming a structure.
1.Things they know
2.Things they want to know
3. Combination of these two
I even used representations in order for them to get it easily so I don't know how hard will it be sharing it to a larger scale of people.