She read all of it, but it was a novel she read TWO YEARS before she died and got reincarnated. It makes sense that she got the details wrong because 1) it was not a novel that left a deep impression on her, 2) she did not read it multiple times to the point of memorization, and 3) it was two years before she died plus the years she grew up in her new life. I don't even remember most of the novels I read last year much less two+ years.
I'm honestly always surprised when all the reincarnation MCs remember all the details word for word when I can't even remember all the details to a manga I read last month ╮(￣▽￣)╭
oh lol ok
so how much did she read? it literally looks like she knows nothing at all