I know beans about writing, but
Mr. Scalzi is a pretty good source. Sure, it's directed at teens, but one of the things he mentions is start getting published... in the school newspaper.
I don't know how your daughter's school works, but I was able to write for my junior high newspaper when I was in the 6th grade. Might be a good way to build confidence and hone her skills, even if it's not fictional writing. I also wrote short articles for my parent's church bulletin. I was more of a reader than a writer

Stephen King and Mary Higgins Clark were two of my favorites at that age.