The beginnings of my masochistic/humiliation fetish started early. My mother says I enjoyed watching comedy shows in which people threw pies in each other's faces, she says that was my favorite thing in the world, I must have been as young as 5 or 6. This makes me suspect that even at that age I was becoming fascinated with humiliation. A "pie in the face" is an act of degradation.
At age 8 my humiliation fetish was provided with intense new triggers, I had a young attractive female teacher who wore attractive dresses and skirts and she was always showing her frilly white slip in class when she would cross her legs to talk to the students who were sitting in the floor. I'd be sitting in the floor in front of her and notice that her slip was showing, I knew that slips were a form of underwear so it shocked and excited me that this teacher was showing her underwear to the class everyday. One day a new idea popped into my head, I wanted to share in the experience of exposing myself too so I unzipped and unbuttoned my pants and let my pants slide down so that I was allowing everyone to see my underwear. I grew up with a very strict mother who was always making the point that a person should never allow themselves to be embarrassed or humiliated in public. Therefore, this freedom of exposing myself and essentially humiliating myself felt wonderful because it was the exact opposite of what my mother had taught me to believe.
As a teenager I was bullied by stronger boys and that in itself eventually turned into a humiliation fetish as I turned an adult. But those early memories of being fascinated by humiliation tell me that I've had this paraphilia since at least 5 years old.