I remember when @navaneeth asked this question and it bewildered me for a long time. This is a very peculiar human character differing from person to person. We all have different memory ranges, some more some less.
But I think I will agree with you when you say it depends on how important do you deem the memories. Just like the alphabets or nursery rhymes, or even some memories with our loved ones when we were younger.

This is one of the best and mind-boggling topics I have come across on here.
Thanks for sharing!