I was reincarnated as a young female count. Using magic to develop my territory

A despicable father suddenly dies after a carnage at his wedding. Martine, caught up in the chaos, faints and wakes up remembering her past life. I was in my late twenties, but now I'm a beautiful 12-year-old girl! And now, as the only daughter, I'm going to inherit the Earl's family and become the...