One in twenty.
Old age will kill after 80-100 years. Ideally we’d live until then.
Grow and learn for 20 years, work and produce for 45/50 years, retire, rest for 20/30. That first 20 years, it’s when you become you. Twenty years out of a hundred.
That first fifth of your life is when the plastic parts of your brain form the framework of all future thoughts. Religion, language, culture; it’s the foundation of a psyche. It shapes your perceptions and how you process the things you learn about the world.
And yet it’s when you have the least control. The world is acting upon you. Your circumstances are not your choice. Parents, citizenship, economic status, community, it’s all foisted on you. All is not misery though. Once you become conscious; once you start reflecting on why you believe what you believe, then you get internal control.
So nothing is locked in stone, you can certainly rebel against any of those, but you’re never free of them. Every decision you make is because of them, even if those decisions are to oppose them. It never goes away.
That first fifth.
The twenty years.