the young lord of house finlanz

My name is Lizbeth, and I am a 7-year-old who will use the knowledge from my previous life to develop my territory! Lizbeth was born as the daughter of Margrave Finlanz. She was married off in a political marriage to Crown Prince Reinhardt as his 10th concubine. To distract herself from her loneliness, she exchanged letters with friends from other countries. However, she was falsely accused of a crime and imprisoned in an underground prison. With no one listening to her pleas, she drew her last breath alone, but... "I've returned to the past---?" When she came to, she found herself in her warm bed, back to being her happy 7-year-old self! The remote territory lady's coming-of-age fantasy starts with a loop! Hip Hip Hooray~!