It is really a normal growth for kids, I started masturbating at the age of 6, I could not really forget it when I was in grade 1, I was still 6 years old that time, what I did was that everytime I got a hard-on I usually touch the genital of my girl classmate inside the classroom using my fingers,(without my classmates and our teacher noticing us of course!) then I also use a pencil to touch her organ with the eraser tip.....I was so curios that I don't know what I was doing......