Was Daniel X a book for kids or adults?

Ok, so I purchased this when I was scanning the bookshelf at Walmart looking for my next novel I wanted to read. Although it's small, it had "#1 NYT Best Seller" written all over it, and although I've never read anything from James Patterson before I have heard he wasn't bad.

So, I read the back, it made it sound like a epic adventure of a boy with extraordinary powers on a mission to hunt his parent's assassin. Ok, now that's something I'm into, space, adventure, danger, revenge... (not that I'm vengeful). I start reading the first chapter and the main character is a gifted 3 year old, and the story is narrated as if the character was re-counting it. Of course he was three, so the writing, thoughts, everything seemed a bit kiddish... fine... then as the book progressed it continued with this "kiddish" writing style... few descriptives, and what there were sounded like a valley girl recounting things "Like he was slimy!"

I'm on the fence in terms of the chapter structure, I don't think more than 5 chapters had more than 2 pages. A TON of chapters were literally one page. For a book 220 pages, there were 91 chapters! At the end of the book I felt like I was still waiting for the writer to write like an adult... it was ok, very kiddish... why it was in the Adult section I have absolutely no idea. Plus, at the end of the last chapter there were ads for other children's books! I was pretty upset to say the least.