C. E Murphy 
Take a chance [EPUB ebook] 

Frankie Kemp’s little boy was killed in the crossfire of gang warfare; ever since, Frankie has put on a mask and gone out to try to stop trouble before it begins. For years she’s been a vigilante in a world where superheroes belong on Saturday morning cartoons–but with the escape of a flu-borne supersoldier virus, Frankie, now called Chance, finds herself a powerless vigilante in a world with superpowers. Experience counts–but will it be enough to keep her alive?