I read this to refresh my Spanish before going to Peru. It started really easy: how many siblings, house description. But just as the story got interesting, it moved onto the next section. The history of Mexico section was also easy to read, and more interesting than the high school story. It was a bit simplistic in its telling of the Spanish v. Aztecs, but I didn’t read it for its historiography. The 3rd section was a Spanish folktale that was interesting in how strange it was. Overall, I felt my Spanish did improve by reading this, but I’m sure there is better Spanish literature to be had.
I remember a bit of the content being culturally offensive even though I wouldn't identify as First Nation. However, if you can look past the few negatives in the ideas expressed, you'll maintain or increase your reading comprehension.