https://www.amazon.co.uk/s?k=earth&rh=n%3A69&ref=nb_sb_noss
https://www.amazon.co.uk/s?k=volcanos&rh=n%3A69&ref=nb_sb_noss
https://www.amazon.co.uk/s?k=planet&rh=n%3A69&ref=nb_sb_noss
https://www.amazon.co.uk/s?k=fossils&rh=n%3A69&ref=nb_sb_noss
I don't think a kids home without 100 science and learning books would be fair on the kids. I'd devote 1 meter by 1 meter at least for it. She will probably change her mind and pick some other interests as a result! Make sure you get the big books for kids, little books are fiddly and made for travel.
At my local flea market shop I think i can get 10 books for a 5er.