The MC is selfish and ignorant to a degree that's disturbing. No matter how much you like books, you should realize that your family members are concentrating on survival through the winter. While you might not mind dying as long as you have a book, that doesn't mean you should be disturbing everyone else who is trying to make sure you don't die. This goes beyond "well she reincarnated as a 5 year old" since the book obsession is completely rooted in her adult values. The 5 year old had no idea what a book was, but certainly should understand what "we need to get ready for winter" means.