The Dan Manning math theory behind the why years seem shorter as you grow older:

Examples: When A baby turns 1, it has experienced 100% of its life in that one year. That one year is 100% of the baby's life. When that baby turns 2, a year is 50% of its life. Time now seems to be moving twice as fast. When that child turns ten, a year is only one-tenth of the total time experience.

So time actually does start to fly by.

Tomorrow, 1 year will be 1/42nd of my entire life up to this point. That's only 2.38% of the entire time I've been alive so far. The years do seem to go faster.

So as you get older, and every year seems to be getting shorter, mathematically speaking, each year is a smaller portion of your entire life experience up to that point.