So I had to sit on this book for a little bit, just because the last half left me feeling very uncomfortable and I wanted to place where this feeling of discomfort came from.
I think that part of it is the fact this book is called "A Sister" and the first half falls into motion similarly as you find that bond growing between them but then in the second half instead of seeing a familial we move into a relationship that makes me feel incredibly uncomfortable.
Partially because of the relationship we are lead to believe to be happening, and also the maturity difference between someone who is Sixteen and someone who is Thirteen. The power dynamic becomes incredibly gross.

It really stinks because that overshadows the well-done relationship building that is depicted and could have been interesting if Sex had not been approached like it was.