Her Majesty's Swarm

Our protagonist is a college student who enjoys playing as the evil-aligned faction Arachnea in her favorite real-time strategy game. One day, she finds herself in a world similar to the one in the game; additionally, her body is now that of a fourteen-year-old girl. While things are a bit different from how they were in the game, one element has remained the same: she is the leader of the Arachnea.