I remember reading this novel in high school back in the very early 90s. It involved a teen girl who wanted to be more than a meek wife in a post-apocalyptic patriarchal society. So she disguised herself as a boy to participate in the rite of passage for boys to be accepted as men.
The group of teens had to go out into the wilderness and bring something back. I believe it was some kind of rock that turned out to be radioactive. I remember the girl being treated for radiation poisoning/burns.
There was also some kind of alien race present in the world, but they were in the background mostly. There might have been a simple cover design of city ruins. The book also stood out to me for its one scene depicting female bodily changes and the character's fear of what that would mean for her.
I've been trying to dig up this book title for a couple of years now with no luck so thank you very much for any thoughts spared for this!