A psychopath is a psychopath regardless of gender. And my own feeling is that it would be far too easy for a female psychopath to satisfy her warped desires if she so chose to. Maybe now is the time we try and change our assumptions and attitudes. I hope not. The other problem I found with writing in the first person was that I would be seen by the readers as endorsing Terry's point of view.
Terry is a cold-blooded murderer.
She is manipulative, she is a liar. But she does make some valid remarks. I'm not suggesting for one moment that society is responsible for creating the Terry Donnelly's of this world, but I do sincerely believe that we can't just wash our hands of these people and refuse to accept any responsibility at all. If we truly want our social structure to work, we have to accept people who we do not particularly like, we have to respect individuality. If someone is nasty and vindictive, I think we should be questioning ourselves why they are that way.