I guess I'm just going to overshare before the site goes read-only since I don't have anything else planned.
My first sexual awakening was the super mario brothers movie. No, the old one. There's a lady named Big Bertha and she punches Bob Hoskins in the face. Then he asks her to do it again.
But my ground zero would have to be Stocking Anarchy. Big Bertha was when I first realized what attraction was. Stocking hit a psychosexual combo on me and also chipped my egg.
Other fictional girls who I strangely related to included the main character of an anime that was popular enough to get a DVD release in the states, but not popular enough for a dub. Sabagebu: Survival Games Club is a show about girls shooting each other with airsoft guns. The main character is an unscrupulous bastard with a superiority complex. The club leader drugs her in the second episode.
Homestuck probably did a lot in terms of both sex and gender, but I'd have to reread it to get the specifics down.