Youth is not a time of life, it is a state of mind. Nobody grows old merely by living a number of years; people grow old only be deserting their ideals.
Worry, doubt, self distrust, fear and despair, these are the long, long years that bow the head and turn the growing spirit back to dust.
You are as young as your faith, as old as your doubt; as young as your hope, as old as your despair.
So long as your heart receives messages of beauty, cheer, courage, grandeur and power from the earth, from humanity, from the infinite, so long are you young.