If nothing is going on in your life, it is as the article says. However, if you experience novel and memorable stimuli, good or bad, time dilates. Traumatic experiences are particularly memorable because the brain wants to make sure you learn your lesson. It is a consequence of the brain's compressive learning algorithm, discarding the familiar and making sense of the new.

My hypothesis is a bit different. Instead of logarithimic time perception, informational time perception. Children have brains with high plasticity and huge new information acquisition (learning) rates. Those rates drop as plasticity decreases when one gets older. Those "bitrates" of new information flowing into long-term memory act as sand flowing through a hourglass. A fixed amount of sand represents a fixed amount of subjective time. When those rates drop, we feel time runs faster, because now the same amount of sand (subjective time, information) stretches over more clocktime.

I don't think it has anything to do with age but with the rate of new experiences.

Take a year off work to travel the world and you'll find your subjective sense of time passing slows right down.

Does it matter though? Does it matter how many experiences you collect? You can't take them with you. Better to develop relationships that can be a source of joy (I imagine. I have not done that).

If you give me back 3 month of vacations in summer as when I was a kid, they will also feel long.