It's a great idea, and the OP and donors are making a big difference. While I was a doctorate student, I supported a Romanian orphanage (run by Americans I never met except via email) with parcels of medicine and stationary (basic stuff e.g. anti-fever pills, coloring pens etc.). Since I never sent any cash, I was not worried about being scammed.

I've also been financially supporting three grassroots projects to help children in three places, namely Lomé, Togo, Caruaru, Brazil and Bhopal, India (via https://www.fkb-bza.de, sorry, Website in German only, a charity that has the advantage of being free of any overhead - thanks to people I personally know and trust that travel there regularly, paying for their own tickets).

Thought experiment (putting back the geek hat on): I wonder if the OP's activity could be made viral and scaled up across the continent:

While there are more donors do:

- for each African country

- pick a seed city c

- pick a seed student s from c

- assign donor d to s to fund s' education

When paying for s.o. education, receiving students pledge to pay it forward by becoming a donor once they get a job that permits to do so or to return to become a teacher for a while.

On top of that, students form or join an online community to support each other and get to know each other (peace is as important as education!).