1. Ferrets are not rodents
2. This book bored the pee-water out of me.
So, I guess you can take it as a twisted (or more realistic?) coming of age story, which contrasts against a lot of the more twee stories that run amok in fantasy literature (most notably, of course, Harry Potter). Or you can take it as a silly novel that has tons and tons of shout-outs and allusions to other sci-fi and fantasy stuff (I did catch a fair amount of them, I know I missed a bunch), but in the end, this book bored the crap out of me.
Quentin gets tested into a super-secret, strenuous magical "college" right out of the end of his high school career. Magical schooling stuff happens. Testing, and inter-personal relationships and shit (you know, because it's a boarding school so they don't have much else to do.) And then they graduate. And then mundane after-college stuff happens, with more interpersonal stuff and betrayals and junk. Then they go to Narnia Fillory, a magical fantasy ("fictional") land that Quentin has, coincidentally, been obsessed with his entire life. Shit goes down. Life goes on. I desperately try to read faster because I'm falling asleep.
I was just bored by the whole thing. If it's a coming of age, I guess I would want something grittier or less in-jokey, than where it went. If it was a fun shout-out to a million and a half sci-fi/fantasy/magical references, then it could be done better. If he wanted to mock and play with tropes - again, it could be done better. Maybe the author tried to do too much. I don't see why such acclaim has been heaped on him. The writing isn't that great, either. I don't know exactly what went wrong, I just ended the book mostly pissed off that they called a ferret a rodent.
The author needs to get his shit straight on that point.