Barbarella, Vol. 1

I think this is the earliest confident, intelligent female who's comfortable with her body that I've come across.

Images are easy to understand due to simple coloring and the text is pretty tiny [thank goodness for 2-finger zoom]. Although there's not a visual clue that you're looking at the next issue in the series, the fact that people come and go, do.

I wonder if the artists for the movie Heavy Metal got their female body shape from Barbarella? Maybe the creators of Barbie, the doll, did too?