Closer to 4.5 stars. 
 This is light science-fiction at best. Dystopian-lite too. No matter, I still liked it a lot. Walker writes everything very well. Her dialogue feels real. The narration contains just the right amount of details. I especially liked the pacing and the flow. 
 You know bad things are bound to happen, because, well, in The Age of Miracles, the earth begins to revolve more slowly around the sun. I don't care if the consequences that are in this book are realistic or not, what matters to me is how they jelled with the story. Jell they did. The weird things that begin happening due to the earth's slowing are doled out in tiny little teasing tidbits. You don't know what, and you don't know exactly when, but you know bad things are afoot. 
 Julia, an 11-year old living in southern California, with all the issues and drama of a tween girl, narrates the telling of the "slowing", in a flashback sort of way. Her parents feature largely in the story, as do some friends and her crush, Seth. Walker nails the character development, providing a distinct picture of the main players, yet leaving just enough unknown to keep things interesting. 
 I love it when a book makes me think. The Age of Miracles not only caused me to wonder about what things might happen to our poorly-kept planet in the future, but also what that would have been like for a girl just starting middle school. I was one of those creatures, long ago, and there's enough going on without (view spoiler)[ birds suddenly dying (hide spoiler)]. Walker also adds in an element of ostracism too. 
 This is her first book, and I sure hope she has more in her. I'm so ready to read 'em.