Status Updates From The Sacrifice

I read this in high school and was spellbound. It's been in my head for years, but it was a school library book, so I forgot its title. So glad after years of searching I found it!

The love story that this book manifested, although due to some ambiguous uncertainty, is incestuous, actually lured me into turning the pages until the very end! The protagonist starts off as a liability with quite a handful of ill-favored traits, and as she approaches the outcome, which I found predictable because of the hastiness of my train of thought, and develops, I inadvertently developed affection for her.