As we get older, we used to be more responsible as we needed to handle more things. During the young age, even if we have commitments, it doesn't look like a big thing. After years, even a small commitment looks like a big thing, and we start the plan for the execution much earlier, and we feel like a great achievement when the same gets accomplished. During our young age, the same could've been done on the go, and we could've never minded it being a big thing. At some point, being selfish is a must. If not, this is going to be difficult to survive in the fast-moving world.
If you look widely out there there are many people who are getting older but are unable to have responsible attitude and often underestimate certain things that are actually problems that cannot be solved easily, basically age does not guarantee anything because attitude is not about age but how the mindset of each individual itself.
Whether they are still young or people with older ages will always show quite significant differences in attitudes to each condition, I think you can understand it when you are able to distinguish the character of each person of various ages.