I recently read an interesting article about myths and realities of the mid-life years (Science Daily Jan 22, 2010). The author of several recently published articles, Professor Carlo Strenger, has made a number of interesting observations. About 40 years ago, Elliot Jacques coined the term "mid-life crisis". At that time, the average lifespan was 70 years and 35 years was seen as the midpoint of your life. People expected that their quality of life would decline after they reached that midpoint so they reacted to the fear of their own mortality and some did things out of character.
Professor Strenger has pointed out that your midlife years are the best time of life to flourish and grow. Based on research, he feels that adult lives have second acts. You take the lessons learned during the first half of your life and apply these to the second half of your life.
I think we can go further than that. I think each decade of your life is a chapter and that you take what you learned during each decade and use those experiences to improve, make changes, grow or expand your horizons during the following ten years of our life. Using the period of your twenties as an example, you have finished school, have your first full time job, may be purchasing your first home and car, getting married and having children. You have made a lot of important decisions during your twenties. These experiences and self awareness add to your knowledge bank of dealing with changes, unplanned situations and growth as a person. I would venture to say that each decade you experience is better than the previous decade because of personal growth and ability to cope, change and succeed.
If we drill down deeper, what we need to do is celebrate our birthdays. Growing up I enjoyed organizing my own birthday parties. I would invite my classmates and I still remember eating hotdogs and orange pop and my parents commenting on the pop spilled onto our dark beige living room carpet. Why we need to celebrate our birthdays is because we have experienced another year of growth, we value our family and friends and pets and our life.