It's a common feeling that times moves faster as we get older. The days quickly turn into months and birthdays come and go with little warning. As a child a week felt like ages, birthdays were impatiently awaited.
My theory is that life feels slower when you're younger because you're almost always experiencing something new. New experiences slow down life. When you go somewhere for the first time it feels like it takes forever. The more you go there the shorter the journey feels.
As an adult we get locked into routines and we know every inch of our surroundings. Journeys that are rare, we've taken a dozen times already. Our home towns are as familiar as ourselves. Most weeks we spend in a rigid routine with few variations. Everything naturally feels faster because there's few things that give us pause. The significant memories at the end of a week are usually those unusual events that stood out.
I think the only way around it is to constantly inject new experiences into life. Maybe at first in small ways like taking a different route home or trying new restaurants. And eventually in larger ways like traveling and experiencing new cultures. That way life doesn't pass us by before we know it.