When I was in my late teens I was already interested in philosophy.
It is of note that for a long time moral nihilism was a kind of unquestioned default position in analytic moral philosophy.
How could it be that I had a legal obligation to kill people I did not know, and who did certainly not consent to it, while my father's doctor could not help my father to die when my farther asked for it? My consternation brought me to moral philosophy and a life-long search for an answer to the question when and why we should, and when we shouldn't, kill.