When I was a teenager and used to bang on about Marx and the Revolution, my Gran would put her hand on my shoulder and say "Even the very young don't know everything."Mark Twain also had a great comment along those lines:
'When I was a boy of 14, my father was so ignorant I could hardly stand to have the old man around. But when I got to be 21, I was astonished at how much the old man had learned in seven years.'