Gender definitions?

For many years, I've had this 'image' of what a woman was expected to be like, and what is expected from a man. I've also had the notion that if a woman deviates from this she is 'unusual', 'not like other women', 'a tomboy' and something along similar lines for men (though I'm sure 'nancy boy' cropped up a few times).
The reason I bring this up is because I've always felt like I'm one of the female oddities. I don't like shopping. I don't have a shoe obsession. I love cars, action movies and science fiction. In high school I was, at first, one of the few girls to do woodwork and in the end, the only one who stuck it out. Sure, I love the shiny, the cute, the teeny, but I rarely felt like matched what a female should be like.
Then I met the internet. After many years of travelling its corridors, I discovered (and picked up a few new quirks), that I'm not the only female like me. There a tons of car loving, action moving watching, sci-fi reading/watching females out there.
So when/where did the lines get blurred? Or was the notion that I grew up with completely wrong?