Powered (Powered Trilogy #1) by Cheyanne Young

Maci Might's sixteenth birthday is supposed to be the day she's awarded Hero status. But thanks to a tiny anger problem and a questionable family tree, King City's elders think it's best if she doesn't join the Hero ranks. Determined to change their minds, Maci will break whatever rule it takes to prove she's Hero material. As her hair darkens and her anger grows, everyone turns against her except Evan; a childhood friend turned scientist who may be able to unlock the secrets hidden in her DNA.

When a villain attacks King City and her dad is held prisoner, Maci discovers a truth she refuses to believe. She may not be a Hero after all—but this time the Heroes of King City need her more than she needs them. And she won't let them down.

Powered is the first in a trilogy.