Back to the actual question. The rest of this just isn't appropriate.

This is a bit alarming. I however chalk it up to several things; a cry for attention as well as a need to control something in your life. If I am reading this correctly, I am guessing that you lacked both these things at the time.

The fact you have concern and apparent remorse for this points away from psychopathy - or at least that is my figuring on the matter. As, these things suggest an understanding they were wrong. You don't mention still having urges to hurt, another reason I have made this conclusion.