Whether children have first amendment rights is a vexed legal question, but what is not in question is that they someday will. Constraining them from expressing their views is no preparation for exercising those rights.
it's a good idea to wait a few months before joining anything when you arrive at a village. A bookseller friend who retired to nearby Oxfordshire, and was worried he might be bored, got himself on to every village committee in the first six months, and spent the next ten years extricating himself.