I wasn't thinking it crossdressing when my GG cousin, a year younger than myself,used to come to our house with her mom to visit.
She would always bring a pair of overhauls(we called them) in a box.
While our parents visited we would go out in the pasture and play like we were a farmer and his wife. We lived on a farm, so I guess that was our role models.
To the point. She was a tomboy,still is, and we would sometimes swap roles. Sometimes she would drag her overhauls out and put them on, and I would wear her dress and be the wife.
So, I guess that was my first crossdressing experience, at the age of six or seven.
I was about ten when she, and her older sister, started dressing me in their clothes when I visited at their home. That was also when I learned I liked girls clothes better than mine.