I remember as a boy (5-6 years old) being attracted to pretty women wearing high heels and heavy makeup, particularly deep red lipstick. Face-down on my bed at night and recalling these images, I got that feeling, and rubbing myself against the bed felt good. Then one time as a preteen/young teen, the first Big O happened. It was a game-changer.
I believe I had sexual experiences long before puberty, even not understanding what was happening and not being fully functional. But what I felt was a sexual response to those women's things that excited me. I think my fetishes began very young but only reached a peak after puberty. In some ways, long after puberty, as I learned through fetishistic crossdressing how to maximize pleasure.