"Why is there no plumbing?" or "Wait, is that magic?"
They have to act like a normal child so people don't think they're possessed. 1 : I Recalled the Memories of My Past Life...
Catching their reflection and realizing their face doesn't match the "soul" they feel inside. 2. The Mental Sensory Overload "Why is there no plumbing
Realizing they have parents or siblings they didn't have before. 4. The Immediate Goal or a specific tool).
Avoid the "inner monologue" trap for too long. Give them something to do:
Seeing an object that looks exactly like something from Earth (a toy, a book, or a specific tool).