I'm so tired of teenagers being "the chosen ones" in fiction. please, let a middle-aged woman save the universe! she's seen some shit and dealt with it. she's tired of it all. she doesn't give a fuck. she's angry. she will get this shit done.
Might I recommend The Future of Another Timeline by Annalee Newitz
Its a time travel book so it gets kinda complicated but in the main thread of the story all the characters are well into middle age. Its also a feminist book so their are no male protagonists at all.