I'm surprised I liked it even this much, considering the prose is so purple it would have cost a fortune in ancient Rome, the characters are teenage stereotypes (from mean girl to meathead and most in between), and that the author, an adult man, spends far too much time focused on the 16 year old female protagonist having graphic sex. He also spends a lot of time focused on the magical boobjob she gets at one point in the book. 

It's very well thought out though. I like an "unconventional school" narrative, be it a school of magic, or assassins, as in this case. The story is tightly woven once it gets going (about 100 pages in), and the climax feels sufficiently built-up. What a twist, too! 

I was near the end of the book when I found out the author also associated himself with racists recently, however, so I'm sorely disappointed and won't be picking up the sequel.