Defaulting to a specific age when recounting childhood memories

I've noticed a pattern whenever I recall/retell snippets from my childhood. No matter when the event actually took place, my brain defaults to 'it happened when I was 3 / 8 / 12 years old'. Sometimes I catch my brain doing it - I'll think about the event a little deeper and realize 'no, you must have been 10'. Often it will go unnoticed because expressing that an event took place at any other age is uncomfortable.

I don't remember most of my childhood, only a few snippets remain. It feels like I didn't exist for most of it. I think I may have been more present for those specific years and that's why my brain defaults, but it's also possible that my perception of time is so tilted that I only think that due to my brain's age bias.

It's hard to think of important events that may have tethered my brain to those specific ages - most I've got is starting kindergarten and slicing up my palm real bad at 3 (I think I was 3 anyhow), another milder and less traumatic injury at 8, and getting forgotten at a gas station on a school trip at 12, though that was more memorable than actually stressful.

Does anyone have experience with this, or know the name of the phenomenon if there is one? I would love to learn more about why and how such a thing occurs. Thanks :)