I do not see how children can ask questions about determinism. God? Maybe, but they won't be very good questions because they are children.
So, adolescents are the youngest dho might ask about determinism, and that's only if they happen to even hear of it. So, again, I don't think such questions would be very good.
And, answers are very hard to come by. So, you're welcome I spent time on this.
Peace.