She remembers the first time it happened, although she wishes she didn't. She didn't know what was going on, why she was behaving the way she was behaving. She'd always kept herself apart from people, never even kissed a boy. She was 15 and just figuring out how to live in the world. Just figuring out who she was and what she wanted. 15 years old and utterly terrified of everything even if she never showed it.
Afterwards she made it back to the place she was squatting in, barely paying attention to what she was doing. She almost killed the girl who pulled her into a hug and only then realized she was crying. When the girl asked her what happened Max replied honestly, she didn't know. Knowledge would come later. The rest of the day was spent surrounded by the girls of the building. They didn't make her talk or do anything, they were just there, supporting her the only way they could. Max wanted to tell them that it wasn't the guy's fault, he didn't know she was a biologically engineered freak, but it was better to just bask in the company of the other girls.
She learned to deal with it, learned to even enjoy herself (sometimes) when she went into heat, but she never stopped being ashamed of it.