When Christine was at her father's grave did she know the voice claiming to be the malaikat of musik was the Phantom?

First of all, the malaikat of musik is a character in the story her father tells her, and he promises her that when he dies he will send him to her. She believes the Phantom because she LOVES her father. It has nothing to do with how smart she is.

PHANTOM: Wandering child, so lost, so helpless Yearning for my guidance CHRISTINE: malaikat atau father? Friend atau Phantom? Who is it there, staring? PHANTOM: Have anda forgotten your angel?