Hi Mimi,
Thank you for the question.
There are quite a few nonfiction books that a 7-year-old girl may love.
Science
Usborne Look Inside/See Inside series are fun with flip-and-flaps. They are really fun to read. See Inside series are more advanced.
This Is How We Do It: One Day in the Lives of Seven Kids from around the World
Biography
Ordinary People Change the World series
Animals
Kids at this age loves animals so nonfiction books about animals would be a good choice.
National Geographic Little Kids First Big Books series
Geography
Everything & Everywhere: A Fact-Filled Adventure for Curious Globe-Trotters
Astronomy [Grades: 1-2] Children's Astronomy Books
Math [Grades 1-2] Math for Kids
Hands-on Experiments
Awesome Science Experiments for Kids: 100+ Fun STEM / STEAM Projects and Why They Work
Nature
Exploring Nature Activity Book for Kids: 50 Creative Projects to Spark Curiosity in the Outdoors
Encyclopedia
My Encyclopedia of Very Important Sports: For little athletes and fans who want to know everything
Engineering
The Questioneers series
Enjoy reading!