Young Justice - Supergirl
Supergirl joins the team after she was discovered fifteen years after being sent to Earth, after being found by Superman himself along with Batman, she joins the team of young crimefighters. Trying to fit into this wonder works, not exactly the hotspot for all things lovely and sweet.
However, being kidnapped by Lex Luthor, mind-controlled while fighting her own team, starting school, not trusting her team at all is quite hard to manage on one plate. Even if that means having a certain relation to someone...
This girl, an angry temperamental sarcastic teen who wears an red and yellow 'S' plastered on her chest for a living (Plus the purple sparkly nail polish!) is a little over the top. But no, this girl is Supergirl, a super rebellious pain in the ass for all things evil.