Despite the dramatic intro about what a ~monster~ she is hiding in plain sight, her own descriptions do not match the definition of antisocial personality disorder (as "sociopath" is not an actual diagnosis). She clearly loves her family deeply, and she obviously cares what THEY think, at the very least, as she goes to great efforts to calculate what to share and when to share it to maximize bonding with her parents. She picks up on relationship problems with her parents' marriage solely through behavior changes as minor as her mom making an off-hand comment about not liking twilight, so she can understand and pick up on others' emotions. Her descriptions of "abnormal" and "violent" behavior arise in response to situations like a bully bothering her little sister. She wants to convince us of what an awful, awful person she is, but then describes loving other people in great detail, even if she doesn't always use the word "love." (She does use it a lot though.)

She may be some sort of neurodivergent, but it reads like someone who took a personality test and has become REALLY obsessed with that being their defining label.