I think that age as a number is not nearly as important as health. You can be in poor health and be pretty miserable at 40 or 50. If you're in good health you can enjoy things into your 80s.
Wrinkles should merely indicate where smiles have been.
Anyone who stops learning is old whether at twenty or eighty. Anyone who...
Age is an issue of mind over matter. If you don't mind it doesn't matter.