But they are not her memories from when Aria was born.
They are an entirely separate lifetime's worth of memories, experiences, and identity that is completely different from Aria when she was born up to the age of 10.
From birth, until the age of 10, Aria was an entirely separate person.
Anyways, we are just going around in circles now.
O . o;
Are we even reading the same manga? She was reincarnated thrue natural child birth with her otherworldly memories lock till the age of ten. She was born with them.
God didn't insert her into a fresh corpse for her to take over, he just did her a solid to avoid the awkwardness of being a mature mind in a newborn body. God even informed her of this before being conceived on this world.
So no, I fully reject your assertation that the additional otherworldly memories effectively killed the old Aria. They were always part of her, and always intended to be released when she reached age ten.
You are free to keep your opinion, even if objectively wrong. But that doesn't change the facts that are presented in the story thus far.