I'm going to start off with the positives. This book is written phenomenally, and the idea of having to grow up is handled exceptionally. As someone who struggled with the idea of no longer being a kid, the story resonated with me. It is very thought provoking and a good book to read a little bit of a day.
That said, I have so many problems with the book that make it hard to appreciate the good aspects. For starters, as others have mentioned, the ending is horrible. Pretty much the entire book, the protagonist has questions. Questions about how children get on the island, why the boat comes, and where they go after leaving the island as the eldest child has to every year. So as the reader, you expect to see those questions answered at the end. But none of them are. It comes off as though the author just thought of the concept of Orphan Island, but couldn't think of the answers to the major questions. Extremely dissatisfying. It just made me feel like there was no point to reading the story.
My second main problem is the message the author sends in the book. Spoilers ahead. At the end of the book, main character Jinny, who chose not to leave the island because of her desire to stay and not have things change, inevitably has to leave. However, it's not because of her own will. As time passes, chaos unfolds and all heck breaks loose on the island. This is because she broke the natural order of things by staying on Orphan Island, which is symbolic of childhood. One of the kids gets bitten by a snake, and realizing the devastation on the island will not stop till she leaves, Jinny finally heads out.
Why is this so bad that I have to mention it? Well, it sends the message that the only reason you should grow up is because otherwise it will cause you a lot of difficulty. That's literally the only reason she leaves. Jinny never grew to realize that perhaps growing up isn't so bad, that there is more to look forward to. This is a REALLY bad message. "You should grow up and leave behind your childhood because otherwise it's gonna cause chaos." Yeah no.
Final point. So growing up is obviously really, really hard. But you know what makes it easier? The fact that your good friends and family will stick by you. You know what would have been a fantastic ending? If all the kids broke the rules in another way, by all leaving the island. Together. It doesn't make sense that when the eldest child leaves Orphan Island or "childhood" behind, they also leave everything and everyone they've ever known. That's not how growing up works in the real world. Jinny could have realized, through the help of her friends, that there is probably a lot to look forward to past the Island. And then they could have all decided to break the rules by coming with her. What an awesome end that would have been.
And as a side note. I thought it would be cool that "Adult Island" or wherever the eldest kids go every year is actually very close by. So the old Island kids can see their past home and friends and look back fondly (literally), while the Adult Island is invisible from Orphan Island because it is the future, it is unknown. Unseen.
Anyway, I'm rambling on. I feel like this might have been ⅘ stars if the author actually made a good, satisfying ending. I don't regret reading this book, but I am pretty disappointed