I'm looking for a book I read as a teenager (a long time ago!) but I forgot the name. What I can remember is that for some reason everyone older than 12 was dead and those 12 and under were left on their own to get by. If anyone knows this book could you please tell me the title and author? Thanks!!!
Is it *The Girl Who Owned a City? From the summary:
A deadly virus has swept the world, killing off everyone over the age of twelve in the span of a month or so. In suburban Chicago, ten-year-old Lisa Nelson and her younger brother Todd are surviving, like all the children in the story, by looting abandoned houses and shops. Although there are abandoned cars in every driveway and lining every street, Lisa is the first child to think of driving one. She is also the first to think of raiding a farm, and the first to look at the dwindling supplies in stores and deduce that groceries come from warehouses. She finds a supermarket warehouse and raids it, enlisting the help of a neighbor boy her own age, but makes sure that he does not tell anyone because she will use the supplies to create a militia.
The first edition cover, from Wikipedia:
Sounds just a tiny little bit like Shade's Children by Garth Nix.
However this is a bit of a long shot. The kids aren't left alone, instead there's a bunch of 'overlords' who are playing a sort power game but using real life as the board. And here everyone over 14 just randomly disappears, instead of everyone over 12 dying. (It's also not particularly old being published 1997)