The Folly of youth seems innumerable, but with age comes wisdom.
The vigor of youth is the engine of society, but with age comes apathy.
Learn wisdom in your youth, stay enthusiastic lifelong.
Youth
The reason a young person might do something that even they might consider funny, or inexcusable looking back is that they possess the adventurous and untamed spirit of humanity, at its most potent.
This spirit, responsible for the "crazy" is also responsible for the industry and creativity that characterizes youth.
Learning wisdom in youth would therefore imply putting in place a reasonable amount of self-imposed restrictions as tools to help direct your energy to positive actions.
Age
Age teaches you how to deal with circumstances and helps you understand life better, especially your life, having explored all you possibly could or want, having experienced so many highs and lows, the machine that is the mind tires and starts to prioritize, it becomes more streamlined, more efficient, it becomes a point design, astutely tuned, intentionally unconcerned of most other surrounding signals.
This could be great as it provides you and society with some sense of stability and higher degrees of predictability, this among other reasons is why older people tend to be more conservative in their outlook.
This is fine, but only to the extent that it does not stall societies progress or discourage creativity and innovation.
Conclusively
Younger people tend to be more naive but enthusiastic and dynamic, and the older we get, the more helplessly streamlined in thought we tend to become, and while the exceptions are plenty, this seems to be the rule.
Keep it fun, keep it exciting, keep it purposeful.