Here's another way to define the negative space that is an "ordinary" American female: what is each of these forces telling her she is?
For most of us, this is Christianity. Being non-religious does not get you off the hook -- American culture is deeply rooted in Christianity. I'm going to use the vaguest expression of Christian principles, here, since it's such a fractured thing: love God, and love your neighbor. At its root, it's a pacifist, community-oriented faith.
Various parts of federal and state governments assert that women have the right to vote, hold office, get an abortion, receive assistance in buying food, not be sexually harassed the workplace, not be beaten up by her husband, etc.
These are the long-term habits of society. From the past, we inherit ideas about how women should behave, what they want, what they ought to do. Some of these are rooted in biology, some in old philosophies and religion.
Feminism, pop psychology, consumerism... each one has a different message. Women as locked in a struggle with men. Women as a pair of boobs that help sell the latest diet soda. Women as needing to control their bodies.
Culture holds up a variety of role models for women; there's a lot of argument over how skinny they are, how promiscuous they are -- how close to the ideal they are, in short. But whether we're talking about the latest swimsuit model or Hillary Clinton, there are complex messages there.
All of these things influence each other, of course. Things that persist long enough become "traditional" -- though even fossilized old ideas can change. Like the one that said women were not capable of serious, rational thought and therefore could not be trusted to vote in elections.
What kinds of messages do the men and women in your world get, from these institutions in their world?