Do you internally 'avert your eyes' when someone mentions being a grownup? Does it feel like too much to always be an adult?
4000 weeks doesn't sound long does it?
A core idea psychologically is that fears are motivating much of our behaviour.
Do you recoil because you think you will never get to retire? There are some pundits in the UK who are stating that may happen as the retirement age is being pushed back and governments are radically reconsidering costs.