I think you can look at life in 10 year increments.
Think about it, from age 0 to 10 you are getting acclimated to the world around you and becoming self-aware.

From age 10 to 20, you go from adolescence to adult all the while figuring out you want to be independent but realizing real life is scary but Fun!

From age 20 to 30, you realize your life is on your shoulders and you want to have a family/kids/house and all that goes with it - though you don't fully realize what that truly means (which is kind of scary).

From age 30 to 40, you realize life is mundane and exciting at the same time - but a lot of responsibility is now on your shoulders.

From age 40 to 50, you are maturing and life is easing up in the responsibility department (kids move out). Life is more stable and contemplative.

From age 50 to 60, you are totally back on your own, in a sense, married but less responsibility but more health worries.

From age 60 to 70, you are enjoying life, reminiscing and happy about the road you have traveled but you are slowing down.

From age 70 to 80, you are concerned with only the basic things in life - sleep, health and companionship, you realize all that other stuff, well is just stuff.

From age 80 to 90, you feel truly blessed but you don't have the energy to do much about.