I am well into my ninthst decade and notice it, except when i drive, or scate board, then I am not slow but the oldest teenager around.
I notice it when I watch the sun setting on the salt watery horizon from my top window. then it goes too quick. but the earth does not rotate faster now*.
here is my theory: In our internal clock, whatever mechanism it is, some digits drop, numbers die off. so rather registering all the previously existing blips, fewer are counted.
The "day for a thousand year" comparison does not hold, because it also mentions the reverse. a "thousand years like a day" speeding up and slowing down for the one that is eternal.
*but it rotates faster than in Joshua's day, when rotation stopped. and rotation will stop eventually, when the universe is really old. the moons rotation has already slowed to once a month, totally from our perspective.
Our movement through time, the most fascinating journey.