system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How come my 4y old remembers last years christmas very well. And remembers everything we did last summer. And I don’t remember anything from my first 4 years? Can’t be the years cause a 60y old remembers his high school pretty well.
gpt
Because those are practically the only memories they have.

The last year or so have been filled with 'firsts' the only experiences they have had. So of course they would be worth remembering.

By the time you are older, you will have experienced those 3-4year old memories dozens, if not hundreds of times, and most of them will have been better, or more memorable than the ones that happened when you were 3.