“Old” is a relative term. Is a person old who has 65 years compared to a person who has 90 years? What would the 90 say to the 65…”you whipper snappers don’t know nothing” (sic)? Conversely, wouldn’t your niece who has 15 years think you’re old at 35? See, it’s all relative. Mom used to say, “I’m not old, I’m older.” I never took the moment to tell her how wise she was.
Perhaps an “old person” is one whose regrets pile up in the mind and their accomplishments become blurry. “The evil that men do lives after them, the good is oft interred with their bones” (Shakespeare’s Julius Caesar act 3 scene ii). There is a time when forgetting is more desirable than remembering.
Maybe “old” has to do with weariness and despair. One of the most poignant remarks I’ve heard on this was from a Hollywood film. When a passerby asked a middle-aged derelict “how’s life,” the response was “taking forever.” How is your life? Is it taking forever? That is weariness and despair. To be tired of life is to be old.
I believe self-perception is the real reason for a person’s feeling of “oldness.” If we think, act, and feel old, then we probably fall into that category. This condition is not chronolically dependent. I’ve seen “old” coming right out of high school.
To paraphrase a master philosopher, “Old is as old does.”