In teen age, you have lot of time and energy but you do not have much money.
In working age, you get enough money, and energy but no time.
In Old age, you do have lot of time and money but sadly not much energy.
These are the different stages of life and probably will remain the same. So if you will just complain about this, you will not be able to solve this problem. So you should utilize your time and energy to learn the new things at the teen age.
While you work, you must save and invest your money with energy, get prepared for the future. But do not forget to enjoy your life, take out some time for you and your family from your busy schedule to have some fun as you know in old age, you will not have that much enthusiasm in you to enjoy. And life is so unpredictable that you never know what can happen to you next day. So enjoy each moment of your life.
In old age, when you have lot of time, you should guide your younger generation and show them the right path to live and follow. Share your experiences but do not try to force the younger generation to follow your path. Every day, generation gap is increasing with latest technologies. So you may not always be right, just share your experiences and principles.
So if you will see the life from the proper angle and live accordingly without complaining, you will definitely enjoy your beautiful life.