I feel like that sometimes, i cant remember visiting our inner world and the other alters can and it makes me feel invalid, hearing their thoughts is always weird especially because im not sure if it was my own thought or another alter

It's helped me a lot to realize every system is extremely different because our brains created them based on trauma & necessity. I get insecure too but just because your system doesn't look or act the same as another, doesn't mean it isn't a system. Keep in mind systems change over time too, especially when you become aware of it and those within interact more or become aware