I had to ask one of my fabulous local librarians, what makes a book "young adult". It seems that many of the so called YA books that I have read, really and truly aren't about young kids. In fact, some of them tackle some pretty big issues. The answer I got is that books are YA because they deal with teenagers (for the most part) and have to deal with young adult issues - like high school, reaching maturity, etc. Put this way, it does make some sense. Ready Player One, although the main character is 18, isn't a YA novel because it does not deal with young adult themes.
This is an easy reading, fantasy novel with a bit of the mystical thrown in for good measure. A good read for around Hallowe'en. I enjoyed it. I liked getting to know the characters, and I like the idea of exploring the "ley lines". It is amazing that with so many words out there written, that it can be pretty hard to read about energy paths, different kinds of power, ghosts, and the occult. It is much like religion - it comes down to a leap of faith, and what feels right in your overall set of beliefs.