This didn't work for me on any level. 
 - The main character was totally unlikable and unsympathetic. She gets a redemption arc that seems to happen because it has to, not because she wants it or earns it. She never apologizes, never changes her behavior, and yet she is forgiven all ... why? The dual past/present storyline just shows how she hadn't changed a bit. 
 - I didn't buy the present-day "romance" at all, mostly because of critique #1. 
 - ***adding after discussing with my book club*** (view spoiler)[ The more I think of it, the more the abusive/unhealthy relationships presented in this book bother me. There isn't a single healthy romantic relationship that I can think of, and unfortunately, most of the abuse is between the teenagers. Constantino is stalking/controlling Isadora, Isadora uses Sebastian just to make Constantino jealous, Sebastian has some weird physically threatening/non-consensual behavior towards Meche, and of course Meche is the worst because she ACTUALLY TRIES TO KILL SEBASTIAN. AND THEN MAKES HIM FEEL LIKE SHE'S THE VICTIM WRONGED BY HIM. SO MUCH SO, THAT HE SPENDS 20+ YEARS PINING FOR HER AND FORGIVES HER EVERYTHING DESPITE HER BEING EXACTLY THE SAME AS AN ADULT AS SHE WAS AS A TEENAGER. The worst part is, Meche getting a happy ending/redemption arc she didn't earn with personal growth or acknowledgement of her faults seems to justify her horrible behavior, and that's not cool. I feel really sad that the message seems to be "it's okay if your friends and significant others are abusive or mean to you, especially in high school, because everyone's like that." (hide spoiler)] 
 - The setting was unremarkable - other than mentioning Mexican foods, there was nothing to make me feel like the book was actually set in Mexico City. I think Oslo was better fleshed out than Mexico City! 
 - The magic was never really explained or described in a way to make it consistent with the internal logic of the story. 
 - (view spoiler)[ Pretty much everything with the grandmother - both her suddenly being a witch herself, and her stroke due to trying to use magic again - felt like a total cop out, added in at the last minute to justify the plot. (hide spoiler)] 
 - The chapters from the dad's point of view felt out of place and unnecessary. 
 - Honestly, the only character I even remotely cared about was Daniela. Between (view spoiler)[having a chronic disease, the abusive treatment she received from her "friends", and the incident with the teacher (hide spoiler)], she was the real sympathetic figure of the book. 
 This gets a big "no thanks, I'll pass" from me.