The fact that the word kunoichi exists tells Temari at a very young age all that she needs to know but never wanted to listen to. When she grows a little older she learns of the main difference between kunoichi and shinobi. It does not lay in physical strength, or in speed, or in aim, or in the mind. It lies in the warm folds between her legs.
Temari has known of sex for a long time, in general terms. There are no cabbage fields and no storks in Suna, there are only mating animals (if you know where to look) and mating people (if you are stealthy).
When Temari is eleven and can't hide the blood when it comes for the third time Baki sensei is given orders to teach her of what a kunoichi is. She successfully dodges him for the first four nights and sleeps in Kankuro's bed. He smells soft and rolls his eyes and tells her to leave, but he doesn't mean it. On the fifth night Baki sensei scolds her and takes her to his bedroom. It hurts, and she doesn't like having Baki sensei that close (inside? Is he truly...?), and he smells strange and musky and it prickles her nose a little. But he keeps her warm against the cold Suna night, and in the morning he orders her to come back the next evening, and reluctantly she does.
The training is thorough, but brief, and Baki sensei doesn't lay a hand on her after it is completed. It takes a while longer for Temari to forget the sharp smell of her sensei's sweat and feel comfortable around him again.
She has always played with the boys, thought of them as equals even when they are different underneath the clothes. It takes twelve days before she stops looking at men, all men, in a suspicious and calculating manner. Kankuro doesn't understand because it's not until a week later that she can even attempt to explain.
In Kankuro's eyes she is still the same, and they wrestle in the warm dry sands of Suna when they play or just can't get along (and Temari almost always wins). Neither sees why she would have to do anything but smile or use force to get anything at all.
Sometimes she wonders how much her brothers know, because she only ever tells Kankuro of the training, and only in vague terms (but Kankuro isn't slow), and she warns him. Because he's her brother and she's protective of her family (did she not think of how it could save him one day when she went down the long corridor to their sensei's bedroom?) so she needs him to know what kunoichi are trained to do, and how he must never, ever engage in pillow talk. Kankuro scoffs and declares that he would never share his bed with someone weaker than himself, and the compliment hidden in the feigned ignorance makes her smile.