When 18, you think life goes on for ever: you have all of life ahead of you. At 67 you know you have, maybe, 20 years and possibly much less ahead. Thoughts turn to what happens when you die.
Is there life after death? Is it like before you were born? I cannot remember anything about before I came into this world so would the same after death be any worse?
As I have said before, all major religions have some sort of belief in an after-life. Wishful thinking? I simply do not know.
It is possible that no-one else sees and experiences what we do. In an infinite universe (or multiverses?) anything is possible. We find it hard to contemplate not existing.
In the meantime, we have to make the most of life. Life is very precious.