If you're not already a fan of the film and you're easily reading material at this level, you can skip this as in the big big picture of things the SF here is just not that good and the characters are told rather than shown.
I really hate to say this but I was glad I read fast enough I could easily get through this in a couple sittings in a day.
If you enjoyed the film and are looking for level appropriate reading, absolutely this could be a good first book. If you can, say, comfortably read
If you have elderly family this hits particularly hard
I read the afterward about halfway through kind of by accident and it hit my like a rock. The book is not very long (one sitting reading) but I stopped to show someone how short it was and talk about the book at the time and when it dawned on me what was happening it really did hurt. If you have family with cognitive diseases like Alzheimer's this book will hurt. Being simple is not a fault here though I didn't happen to personally learn any Japanese from this book...I would recommend it if you'