the mind of a child

i went to the beach today and while sitting there in the sun, i was listening to some of the kids play around me. it was interesting to me to hear the things that these kids cared about, nothing really out of the ordinary, just the basic things but things that just don't really matter. this then caused me to compare it to an old person who is on their death bed, and the only likely and probably things that they would think on would be death and what would happen after death and the things of life after death.
so, why the change? how do we go from simple having fun to thinking only of the things of the next world? while i may only be 19, it seems to me that the closer we get to death or the time that is suspected for death to come, the more we tend to think on it. no baby thinks of death, but a 110 year old person should have it constantly on their mind.
while this may be the norm, what if it wasn't? the old are always saying how they wished they would have lived while the young are always saying how they are going to live but what if the old lived how they had wished while the young would live as they plan. much more would be accomplished if the youth embraced their youth and if the old would train to youth how to do it.
i am a 19 year old who shook hands with death then turned and came back. i would say that i am one of the few youths who are living as the elder because i now feel like the elder. with this though, even though i have made mistakes that i already regret, i now can live the life that i would have wanted to live if i had lived to an old age. the youth must start to act old when they are young so that when they are old they will then have a life that they can be proud to have. we must live the lives that we plan and not just simple plan them.