Reddit mentions of Why Life Speeds Up As You Get Older: How Memory Shapes our Past

This is at least partially the case, as described in Why Life Speeds Up As You Get Older.

Another part of it is the fact that when you're young you experience all kinds of new things all the time. As you grow older and routine sets in, you will long periods of time with relatively little big changes or new experience and those will kind of merge together in your memory.

You don't remember every single time you made breakfast or drove to work, your memory of those actions consists partly of the last time you did such a thing and partly a blend of many other times you did so. The more monotonous your life becomes, the harder it is to distinguish between specific days/weeks/months/etc because of this effect, which makes those periods seem like a shorter time. A "trick" to diminish this effect is to do new things often.

There are more reasons he explains but I don't remember, these two were the main ones though iirc.