I highly doubt that you are at risk for becoming a sociopath. It’s sad but true that many kids’ curiosity prompts them to hurt or even kill an animal. They are learning about life and death. Almost always, they are shocked by the fact that the animal doesn’t come back to life like they do in cartoons. This is the path to developing a conscience. If harming animals continues, it is something to worry about. But as a one time time event, it doesn’t suggest to me that you have an essential psychological problem.
If you were seeing me, I’d be interested in why you are so bothered now about an event that happened over half your life ago. Why are you questioning yourself? Has something happened recently that has you worried about your moral code or conscience? It would be more helpful to your mental health to be looking at issues in your present than in your past, although they may be in some way connected.
I wish you well.