It's the midlife crisis.
You're fifty and a bit, and one day you wake up and realise you will never be the female equivalent of Leonardo da Vinci, and no one will remember who you were after you die. Time is slipping away. Quicker than you ever thought it would. And gravity has overtaken your skin and flesh.
Is there a proverb, or succinct idiomatic phrase that expresses the realisation that time is fleeting and you haven't done the things you hoped to do when you were a young slip of a girl?
I know the idiom it's never too late, what I would like to know is thereif there's an expression that conveys the fearfear it is too late.