A sibling can remember your childhood without owning the explanation of who you are now.

Someone who was there for the early years holds evidence nobody else has, and that gives their account of you unusual authority. But being present is not the same as being right. They saw a child from their own position in the house, with their own stake in the story, and the decades since are mostly outside their view.

When a sibling explains you to you, take the memory and leave the conclusion. You can agree that something happened and still say, without argument, that it no longer describes the person you have become.