Be with me (Ciel X Oc)

What would you think of Francis and Alexis Leon Midford has three children instead of two? Edward Midford has two younger sisters that are in fact twins. Elizabeth Ethel Cordelia Midford and Rose Ethel Rachel Midford are the complete opposite. While Elizabeth is energetic like her father, Rose was like her mother and her uncle. Rose is very mature for her age. Her and her cousin are very much alike. Ciel and Rose are closer then Ciel is with Elizabeth. Rose helps out with Ciel's investigations and she knows his secret. Rose and Ciel fall in love but Elizabeth becomes jealous. What will happen?

P.S. I'm making Ciel, Rose and Elizabeth all sixteen in this.