I've gone few a few deaths around me: Two pets, my great-grandmother and a classmate (didn't know him more than 6 months, so I was mostly shocked and less sad. But he was a returning student, so I felt mostly guilty about not being as grief-stricken as some of my other classmates who had known him since before he left). I've also seen more than my share of dead animals on the roadside, which always disturbs me (Doesn't really matter in what third-world country your're in, nobody cares enough to get rid of a dead dog from the road or sidewalk).
I was just about to post that I have never seen a living being (beyond bugs) die with my own eyes, but now I remember that I have actually killed a living being (Bugs still don't count, somehow).
I remember the time when I took care of yet another unfortunate animal to be our cat's latest victim. Unfortunately, unlike the others that were either already dead (So I had to throw them away, because my mother, sister, and younger brother didn't even want to look at them) or alive and well enough to run back into the wild, my mother deemed this little bird to be too injured to be able to even lift off the ground if I put it outside. She asked me to wring it's neck and throw it away. I did so, and felt extremely weird (and somewhat shocked) that my first witness of a death was due to my own actively causing it. I think I was 15. It was disturbing, but I quickly moved on (or repressed it, however you want to look at it)