Title: New Sister. Sentence 1: Patsy was 14, and had always been an only child. Sentence 2: Her parents wanted a bigger family, and adopted 13 year old Jill. Sentence 3: Patsy was wary of the new child - what if they didn't get along? Sentence 4: Things were tense until Patsy turned on music, and Jill lit up.
They both loved the same band, and the bonding between sisters began.