When I started university I was in the middle of writing a piece of fan fiction. Yes, I had ambitions to write a grand, important, literary novel (I was going there to do a degree in English Literature and Creative Writing, after all) or maybe just a kids’ book. But at that time the only thing I was actually writing was a spin-off from the original Alien movie trilogy about the one character that survived at the end of the third film.

When Cath follows her twin sister to the University of Nebraska at the start of Fangirl, she is also in the middle of writing a piece of fan fiction. Her story is set in the world of Simon Snow, the star of a phenomenally popular series of British fantasy novels where Watford has a school of magic (rather than a motorway), and where other similarities to other schoolboy wizard stories are purely coincidental. Cath used to write fan fiction with her sister Wren, but when Wren gets to university she seems more interested in experimenting with alcohol, parties and, worst of all, boys.

So Cath finds herself isolated, reluctantly dragged out to eat proper food by her acerbic and quite impenetrable roommate Reagan, and consistently bothered by farmboy Levi, who may or may not be Reagan’s boyfriend, but who always seems to be hanging around the room Cath and Reagan share anyway. Cath really just wants to retreat into the safe world of Simon Snow, a world she understands and can control, but nobody – from Reagan and Levi, to her sick dad and estranged mum, and the professor who dismisses her fan fiction as plagiarism – seems to want to let her. And slowly, she begins to see why.

Rainbow Rowell has written a very affectionate paean to the writing of fan fiction. I imagine it’s how most of us start: by wanting to recreate the magic of a story we have read or seen, and then realising that we have the power to do whatever – and go wherever – we like with it. Writing in someone else’s universe allows us to practice creating stories without having to build a world or invent characters from scratch. Eventually, however, in writing as in life, you have to step out of someone else’s shadow and make your own world.

This book came to my attention because John Green recommended it, and I can see why. It’s very much for his kind of readership, for fanboys as well as fangirls, and indeed, given I still related to Cath almost a decade on from university, very much for introspective writerly types of all ages, whether they’re entering their senior year or their dotage.

Plus I now know what hip-checking is.