At what age are you no longer in your youth?
Choose a number. One's as good as another. It's a matter of maturity.On the other hand somebody once said that forty is the old age of youth but fifty is the youth of old age. It's all a matter of perspective.Or we could borrow GBS's line: Youth is such a wonderful time of life that it's a shame to waste it on young people.
When you mature enough to want to settle down and realize life isn't a big party, I would think.
Its all in your mindset, youre as old as you wish to feel.