That was my thought too when I heard this. Maybe she had a mind regression and could only deal with it like a kid, or only remembered her past life when she was a bit older?
Maybe she only had vague memories? Like being middle class, Korea, and being killed? So she had memories of an adult but still had the mindset of a child?
I think it was mentioned that she remembered her past when she was 6-7....
So I guess the timeline fits? Also if I suddenly without warning remembered I was a grown ass adult that died in the prime of my life to an abused life and no modern plumbing, I'd cry to lollll. I mean, if get over it eventually, but man. These isekai heroines have amazing adaptability skills!
So the MC in the first life was a girl from Korea but then she got reincarnates as the daughter of a rich noble house and the way she talks she's probably mature enough, but in chap 4 her grandfather stated that she was a crybaby meaning that in her first life she would cry because of her cousin's teasing, but is she really that childish to cry of a 10 yearold's teasing, considering she's a reincarnator from the first life and that has a mature mindset-