Giving up my Prince to the Heroine

When Sofia died due to an illness, she reincarnated as the daughter of a duke and currently engaged to Prince Damian. Later on, she discovered that she's one of the characters in a novel entitled "Thorns of Love", the best selling book during her time as a High School student. Furthermore, she's the most unfortunate character in the story, the villainess who died from the hands of the Prince she loves the most. Sofia decided to avoid to take the same path and think some ways to annul the engagement with the Prince. For some reasons her plan for annulment isn't that easy to achieve, so she decided to became a cupid for the Prince and the Heroine to get away from engagement and also to gain the trust of the Prince. What if her plan backfired? She changed the story without knowing the changes of the people around her. What if the Prince didn't want to let her go? What if her plan will be the cause of her early death?