The same happened to my old "...@hotmail.com" email, Microsoft deleted old childhood emails, still bitter about that. Per https://answers.microsoft.com/en-us/outlook_com/forum/oemail... , the limit is 365 days of inactivity.
Likewise, so many amazing memories lost. I wish I could look back to how naive and childish I was at the beginning of my time online.
I'm not sure if it's good or bad (probably a bit of both) that much of my early time online is largely gone--and I didn't have a significant time "online" before I was about 20 or so.