Reincarnated as Subaru's sister (RE:ZERO X OC)

In her previous life, she worked as officer workers until death. Now, new life, she was reborn into the normal Japanese family, with new parents, new brother and new appearance. Natsuki Kyoko, the eldest daughter of Natsuki Kenichi and Natsuki Naoko, the older sister of Natsuki Subaru, have been going through the boring life. She have to study hard again in this life and working as officer again like a hell. But her life still colourful because of her extrovert family. She doesn't need to worry about the boredom that she will faced. Until one day, She accidentally transported into another world where elf and magic exist. Being granted by unknown power yet the weirdest thing that have happen herself, she was chosen to be th fifth and the last candidate Dragon Maidens for Royal Selection. No, EVERYTHING IS GOING WRONG!!! Why would she, who don't know about leadership, being chosen to be the future king of Lugunica!!? But, she let that slide because of the handsome knight who found her that night. "Please marry me."—Natsuki Kyoko. "My apologies again. Thank you for asking but I'm not interested in a relationship with anyone right now."— Reinhard Van Astrea Walk into journey of Natsuki Kyoko in Re:Zero world with her brother, Natsuki Subaru. Together, she and her knight, Reinhard Van Astrea, will through this trial in order to become the rightfully king of Lugunica!! "But, can a witch, who being subject of hatred, become a king?" * * * English isn't my first language. Probably have grammatical errors which I really really sorry. This is my first time write fan-fic especially the smut one. So, yeah, I just finished watching Re:Zero until season two. I don't read the light novel. I do some research on Wikipedia about Re: Zero too but I'm afraid some of them maybe unrelated or misinformation, so forgive me. There will original plot and original character including the change canon events. Please don't judge about that. Also, I'm Reinhard's simp.