Im unable to feel empathy

Hello there. Im a 17 years old boy.

Im unable to feel any empathy. Some peoples of my family even noticed it and told me.

For exemple, when I see peoples complaining, crying, wanting to die, I dont feel anything, truly. I dont care, at all.

Im also very impulsive so even if I am around my friends, if one of them offense me just with a word, I hope they die very soon and painfully and Im happy to imagine it.

Anyways, about empathy, Im just unable naturally. For exemple, I watch documentary with childrens in wars crying because their family died, I read post on forums of depressed peoples, but I dont feel anything. I just dont care at all. Truly, I couldnt care less.

The thing is that I see myself as a good person so I dont know why I am like that.