My mind drastically changed several times, and I somewhat remember how it worked previously.

Do you, or do you think you remember? Your memories are always distortions, not accurate snapshots of reality.

Have you never thought you remembered something with clarity, only to be told it's impossible because it never happened? Or another example, I often vividly remember something from a book (it was a photograph on this side of the page, lower right corner) and then when I look it up, it was in a different location and it wasn't the photo I remembered. But my mental imagery felt so precise!

I'm with grandparent, I think I would perceive my younger self as simultaneously familiar and alien.