One major characteristic of the Aged is Wisdom that comes from the wealth of experience. And this is also what is lacking in the lives of Teenagers and young adults, whose lives are characterized by Strength is also known for naivety and lack of wisdom.
This is the reason they always fall into the same pitfalls that comes with their youthful days.
Experience they say is the best teacher, and the compilation of experience is what amount to wisdom. That is why this book was written.