As the mother of two fifteen year olds I can assure you that they definitely do not "know exactly what they are doing". Their understanding of the world and how other people respond is at best patchy. There is a good reason why they have no vote and are protected from men 30 years older in law.
Whilst the 15 year old must take responsibility for her actions, to the extent that she is able to conceptualise the outcomes, that standard surely applies to OP too.
The 15 year old will know that calling Child Services will be a load of hassle, and she might think they will uncritically take her side, so that her cry for help will be heard, and her father and OP will be told to parent her differently, and she will be universally acknowledged as the victim.. But she definitely will not be able to conceptualise the fear and perhaps shame that she has dumped on her father and OP, nor that there might be negative impacts on her relationships. Her maturity seems more like that of a child who dramatically packs their suitcase because they can't have biscuits for tea- so emotionally she is about ten years behind.
Teenagers are typically selfish, traumatised children have a lower understanding than their chronological age. In addition, the developmentally normal thing is to be separating from her parents and becoming independent. That's all going to be a difficult mix.
It is understandable that OP wants to step away from living with her, but she isn’t blameless at all. That's actually where I see the real problem down the line- the most likely outcome is that DSD will sort herself out and have a happy productive adult life. I can certainly imagine a situation where she comes to OP and her father and says, "I felt your hate from the off, and I know my happiness is despite your best efforts. You knew exactly what you were doing, didn't you?"