Tearmoon Empire – Nozumu Mochitsuki

Twelve-year-old princess Mia is petty, selfish, and oblivious. Five years later, the Empire having fallen to economic collapse, famine, and revolution, she is imprisoned by the revolutionaries. Three years after that, she is sent to the guillotine. She awakens as a twelve-year-old - with her memories of those years intact. The new twelve-year-old Mia is petty, selfish, and determined not to lose her head a second time.

An entertaining book. The running gag is that she keeps doing the right things, the second time round, for the shallowest of reasons, and people keep attributing her actions to noble motives and brilliant planning.