When I was 16, I really questioned a lot of it. Am I really sexually interested in hurting people? It bothered me a lot, and at the time I didn't look at porn because I shared a computer with my family, so I had no idea that these interests were shared by a large group of other people. It was a bit undefinable as I didn't feel like I ever wanted to hurt anyone, really, you know.. if it were mutual or something would be the only acceptable time. But it was still worrisome, as I didn't know if it was going to only expand from there. Being 16 at the time, I could foresee my sadistic side becoming bigger and bigger and didn't want it to get out of hand. I don't think it has at all, it expanded a bit, but then eventually stopped (for now). And there doesn't seem to be any cross-over from fantasy and reality. This part is going to be a bit TMI: I used to force myself to masturbate to vanilla thoughts, but they always swayed over to the dark side and it seemed like I couldn't help it. It's very frustrating, and after leaving and coming back a few times in the past, I have finally just accepted that I'm really into this type of stuff. On the plus side, I decided I wanted to become the best kinkster I can be. So I listen to people a lot more, and try to understand my interests better.

I didn't mean to keep the focus on me entirely, I just thought that personal experience stories can be helpful in case you ever felt similarly; I think you're going to be fine.