Is this really evil?

At the entrance ceremony of an academy attended by noble daughters, the protagonist sees a girl with distinctly pink hair and assumes she is the heroine, realizing that she herself is the villainess. Though she doesn't know what kind of story world this is, her fiancé appears to be nothing more than a capture target—an intellectual glasses-wearing son of a prime minister. So she decides to take action right away to guard against template developments. *On May 21st, a diary from the heroine's perspective will be included in the afterword.