There is a fountain of youth: it is your mind, your talents, the creativity you bring to your life and the lives of people you love. When you learn to tap this source, you will truly have defeated age.
Youth, Aging
Age is no better, hardly so well, qualified for an instructor as youth, for it has not profited so much as it has lost. One may almost doubt if the wisest man has learned anything of absolute value by living.
Learning, Youth
Age doesn't matter: an open mind does.
Learning
At a certain age [...] you start thinking you might have learned something when you were young if you hadn't already been so smart.
Learning, Young