Playing the Supporting Female Lead in a Period Novel

[A full subscription costs only as much as half a cup of Coco milk tea. Thank you for supporting me, cuties!] She wakes up to find that the unlucky supporting female character in the novel is actually her, while her childhood friend and neighbor, the older brother she grew up with, turns out to be the male lead! Chen Jiani: I have a thousand, ten thousand things I want to say to them! They're already engaged. What am I supposed to do? Premise: A girl who was determined to get into Peking Union Medical College becomes an agricultural expert.