Above the Sky by J.W. Lynne

SPSFC

Eighteen-year-old Seven and her best friend, Ten, live where all is peaceful ... except for the violent war raging above the sky. Humanoid robots and self-operated drones tend to everyone's needs, leaving people free to spend their time stimulating their minds and enjoying life's pleasures. But there are strict rules and few choices. Every year, on Assignment Day, the path of each eighteen-year-old's life is laid out by the Decision Makers. Some are given the jobs for which they have shown exceptional aptitude and are "paired" for mating. The others are sent off to fight in The War and never return. When Assignment Day comes for Seven, the assignments shatter everything she has ever believed. For the first time in her life, she is certain that the Decision Makers have made a terrible mistake. But the only way to right this wrong is to do something unthinkable.