Sarah Marie Jette has a list here around books for siblings and scientists (https://shepherd.com/best-books/for-siblings-and-scientists) and she recommends "The Care and Feeding of a Pet Black Hole" By Michelle Cuevas
That is only kids one in our database of book recommendations right now.
But, this one might be cool for both of you, just not sure on age match: https://shepherd.com/best-books/the-universe
Black Hole Survival Guide By Janna Levin
It has illustrations the recommender says, but just not sure if you could help translate the wonder to her age.