This is brilliant and I wish you all the very best.

Can I ask about safe-guarding? It's not the first thing you think about but if you cast your mind back to Airbnb or Uber, their biggest issues were safety.

I would imagine background checks would be insufficient - do you plan to monitor / record sessions? What training is in place for the 30k volunteers? Will there be mentors / chaperones who can drop in on calls and check?

Even with the best of intentions a middle aged guy trying to teach statistics for two hours a week to a 16 year old girl is going to be awkward. Without the best of intentions that's a minefield.

That said - hope you blow the doors off!