There is a simple scientific explanation for the common observation that time appears to pass more quickly as we get older, which is this: Time really is flowing at an ever-increasing pace.
This is a natural result of the expansion of the universe: In accordance with Einstein's Theory of Relativity, as space gets stretched out time is correspondingly compressed. So if the minutes seem to be flying by far faster than they did when you were young, console yourself with the thought that it's not because you are now old - it's just that time is flowing faster than it used to.
N.B. This is clearly wrong, but I still think it's a great explanation.