Official translator is JNovel Club, for pirating ik that Nyaa .si has it complete but you'll need to torrent. The entire main story (excluding side story collections, fanbooks and the spinoff that takes place after the main story) is 33 volumes long but it's split into parts (basicaly arcs) so you don't have to read it all at once if you don't want to.
If you buy from JNovel Club, you get DRM free epubs and if you pay for subscription you'll get some coins that u could buy a book with and get access to pre pubs, basicaly a weekly translations of a book that they currently translate, I would only reccomend the subscribtion after you finish the whole series bc the current things getting pre pubs are the spinoff and the fanbooks. If you're not sure about stuff there is a reddit that has a link to a fan discord that many people use. Sorry for talking too much
The first thing that shows up when u search is ||Hannelore's 5th year in the royal academy|| alias the spinoff that takes place after the main story with another character as the protagonist (kinda weird that if u search it it comes up with everything other than original light novel first). You can buy the entire series here: https://j-novel.club/series/ascendance-of-a-bookworm
every volume is available in digital and paperback. I would reccomend getting the first 3 volumes from the beggining (part 1 volume 1-3 since that's the part in LN) to know if you're into it then buying it by parts as they are listed.

Where can I read the novel?