A teacher contacted me with this question. He teaches at 8th grade, 14-15 year-olds.
What I found on this topic are these two questions in FAQ ‘How do you ensure anonymity and privacy of the people who donated their voices?’, ‘What does it mean that I can’t “determine the identity” of speakers in the Common Voice dataset?’.
If I got it right, it’s ok for the minors to participate. Correct me if I’m wrong.