Youth is when you're allowed to stay up late on New Year's Eve. Middle age is when you're forced to.
Old age comes on suddenly, and not gradually as is thought.
old age, suddenly, gradually, thought
Age appears to be best in four things old wood best to burn, old wine to drink, old friends to trust, and old authors to read.
Forty is the old age of youth, fifty is the youth of old age.
forty is old age, fifty is youth of old age