No, because the same selection bias that chooses horrible and incompetent adults will choose horrible and incompetent teenagers. Have you seen the state of student politics?
yes because it would have a term limit. not always forward progress but the new talent coming in & getting a chance to improve things would be a powerful way to insure we kept revolving.
Given that adults are directly responsible for 100% of all genocides, pogroms, ethnic purges, climatic change events, corruption scandals, financial scandals and most every other major atrocity in human history - I'd be find with turning control over to the group that doesn't contain the entire subset of people doing bulk, horrific harm.