Comment by qingdao99

This was my guess. I believe I have experienced this as an adult too: I played on a special Minecraft server (an anarchy server) for a year or so, and despite spending so much time on it, I can hardly remember my first few days on there. I have no memory at all of being at the spawn location. I believe it's because of what you described - as I continued to play on the server, my understanding of how it worked changed completely so my initial memories no longer made sense under my new framework.