She Was the Real Daughter

The day after I fought with my mom, I found myself in someone else’s body. As if that weren’t bad enough, the body she’s possessed happens to be…
“I became the villainess having only five years to live.”
I, on the other hand, was also a fake daughter who deceived the duke for a staggering nine years. And the real daughter is scheduled to return in a year, having become an outstanding magician, alchemist, spirit-tamer, and healer.
“When that time comes, imprisonment will be the minimum and death the maximum punishment.”
How can the fate of the villainess be changed?
“Why bother thinking about it? Obviously, I’m going to escape.”
Actually, there was another way… but it’s no longer an option. Ugh, didn’t expect that. Seriously. But hey, author, why did you write it like that?
“I will definitely escape from this place before the real daughter returns in glory!”
“I’ve never talked to Ethan about this concern. But I did with you,” the protagonist’s father, Duke Croft said.
“I’m fine now, Ellie. I wish you were too,” said the protagonist’s eldest brother, Ethan Croft.
“At the moment, the princess seems to expect nothing from me. So, we might become a decent couple.”