Depressing and inspiring. My dad gave me seven stones once. He said each is a decade of time you have. Then took two away, and threw them. He said use the rest as you can.
I would throw one more. Because: 20 years old is too late to start any personal development, try this approach with stones to 10 years old instead. 50 years old is a final point due to "A Mathematician's Apology" by Hardy.
Is that a reference to the book or a genuine opinion?