I really can't remember a time when I didn't have/carry a knife. I was a kid in the 60's and it was completely normal for most boys to have a pocket knife in their pocket along with all the other bits and pieces that can be found in any boy's pocket. Carry it to school? No problem. Just don't get caught carving your initials onto the bathroom doors. To me, a knife in my pocket has always been a natural part of a man's attire, kind of like a belt or a shoes.
I can't really say that I was catching the collecting bug, but I slowly seemed to have more pocket knives around the house for a couple of decades without me actually consciously 'Collecting' them. In fact at that point I probably didn't even realize that individual knives had names. I just thought of them as "My small or large Spyderco, my Buck, or my Kershaw". Then about four years ago I went to a local gun and knife show with a friend who was a pretty serious knife collector. We spent about eight hours going up and down the isles and him showing me all the differences between models and brands, explaining the differences in blade steels, etc. I'd have to say that was the moment that I consciously became a knife "Collector". I bought four knives at that show, and there probably hasn't been a month go by since where I haven't bought at least one blade.