I think time goes by faster the older we get for 3 reasons, really many, but the 3 are: 1)We realize how little time we have left. 2)When you're young, you always think you have plenty of time to accomplish things, that is of course if you've figured out what exactly you want to accomplish (many don't even reach that stage until they are much older than they realize). 3)Regrets of wasted time.

There are more of course. Thanks for sharing :)