I don't remember the details, but as a very young kid I learned about the concept of death, and that every single one of us IS going to die, and that most of the ways people die are less than desirable to me, and after a lot of thought on the matter, I decided that, if at all possible, I wanted to choose the when and how of my own death.
In other words, death itself never scared or concerned me, but the unplanned, actual death processes did, and I've known since then that, if possible, I wanted control over that process for myself.
Fast forward several years to middle school and we had an assembly all about how "suicide" is bad. That's when I learned the word, and was frankly grateful that there was a word to describe it, and I was very confused why people thought it was bad in general. (I did, and still do, feel that some suicides are bad, not in and of themselves, but the individuals' problems don't appear, to me, to warrant suicide, or they were clearly horrific deaths, that I just wouldn't want anyone to have to experience).
Over my 50+ years, my views have refined a bit. I strongly believe that suicide is a personal liberty, but more than anything, it still amazes me that there are so many people who don't believe this.