I had also started pretty young retracting. I can't place an exact age, but by 5, my foreskin was retractable enough to see most of the glans with exception to the sulcus. I can recall a couple of play experiences with a couple of male cousins, one about two years older and the other a year younger than me. In summer get together with the family at our grandparents home, we, the boys, would take baths (showers) together. One year I was about 7 going on 8 then, we got in the bath and after playing around with the soap and water. My older cousin who about 10 or near there got an erection and he pulled back his foreskin to completely show his glans plus sulcus, in his way sort of showing us what could and making the challenge, can you do this?
Hadn't initially noticed but I too had gotten erect and followed suit. I retracted mine to show off my older cousin but I couldn't take it back past the edge of the glans. I didn't know why but I learn something then by observation. The younger cousin didn't want to retract his foreskin, couldn't say if he had problems with his foreskin or he was just scared. He was left alone.
The experience drawn took me to the point of playing (masturbating) more and more with my penis to figure out why my foreskin wasn't functioning like my cousin's. One day, I was 9 by then, I was taking a bath, this was typically the best opportunity to play with my penis and my playing activities then were comprised of yanking down my foreskin down to the base as far as I could. The yanking and keeping the foreskin pulled back tightly would cause the tip of my glans to curve down a bit. It was a pretty nice sensation pulling the tip of the glans down and stretching the skin, I surmise that what I was really doing was manipulating the frenulum area by stretching the surrounding area. I did this numerous times on this occasion which ended up causing me what I would say was my first full dry orgasm which also resulted in ripping the adhesion between the glans and the inner foreskin. I had finally seen the sulcus of my glans for the first time. I believe it was a pretty prominent one.
I had been attempting to keep my foreskin retracted like I had observed on my father, since at least the age of 6 but I had very little success with the foreskin staying back behind the glans. After the ripping of the adhesion the foreskin was more easily staying back, not permanently however. It would often slide down and but I kept the efforts up and my glans had already acclimated from all the earlier failure attempts I had done through the years.
In the ensuing years after the adhesion removal, retraction become more long-term. By age 14-15 I was nearly full time retraction. I believe a couple of things helped, the sulcus exposure at 9 and going through the puberty process, I am sure the glans grew enough to retain my foreskin back behind in most instances like a dam. However like all dams, they have their limits and on occasion the foreskin would just overtake and creep over the head.