After Being Abandoned, the Eldest Princess Became My Biological Mother

I am a fake daughter of the Prime Minister, I have known it since I was born. I was still young at that time and could not find my biological parents. Until I saw the real daughter for the first time, I knew it was time to leave. Before I could sigh that my life as a salted fish was about to end, I discovered again - the house where the real daughter grew up was actually the palace of the eldest princess of the current dynasty! Am I the eldest princess? ! ! The real daughter seems to regret it. Sorry, I declined.