I voted "under 6" because that is the age when it all started My mom first tried to potty train me when I was only 13 months-old. I kept going in my pants at that age so she put me back in diapers. Then she tried to potty train me again, at the age of 2 to 2 1/2 years old, but I would not, or could not, stop going to the bathroom in my pants: especially pooping, I pooped my pants in both diapers and training pants. After a while, my mom gave up and put me back in diapers again, at 2 1/2 years of age. She kept me in diapers and rubber pants until I was almost 5 years-old.
But then, less than a year later, at the age of 6, I saw a baby boy around a year old at my friends house suddenly turn red in the face and poop his pants in front of everybody and then his mom changed his poopy diaper right there in the living room with everyone watching, and the living room smelling like poop and baby powder. After that day, at the age of 6, I had a hunger; an insatiable desire to travel back in time and be a baby again, messing my pants in front of my mom and everyone else in the room.
At that point, at the age of 6, I started stealing diapers and rubber pants and diapering myself in secret, traveling back to my days of infancy when I made a mess in my pants and my mommy changed me in front of everybody. I am almost 60 years-old and that fantasy of of being a 9 month-old in diapers pooping my pants in 1959 has NEVER left me.