People like to read very different things at different ages. We’re targeting “middle grade” and up, which gets defined as 8+ or 9+, depending on who you ask.
It’s probably safe to say it will appeal to most 8 year olds, absolutely all 9 year olds, very bright seven year olds, and a handful of five-year-old geniuses. Plus most adults.
If you enjoy the Lemony Snicket or Harry Potter books, you should have no problem reading Loose Strands.