Honestly does she even need her past life's memories if she's this dumb.
Like I get that she's in a child atm. However what's the point to having memory / intelligence of your past life...
Also the enviroment she is in, and the story is trying to be comedic with her brother. Forcibly comedic.
Seriously dark, abusive enviroment tries to throw in comedy by using
fart jokes, and big brother have my food (baby formula milk) cuz im considerate and want to feed you.