Can Lena Ever Become a Hero on 'Supergirl'?

Lena Luthor's stance on morality has been the heated debate circling her character since her debut on Supergirl. Season 3 has already returned to this, twice, and forced Lena to entertain the idea of killing someone to protect herself (and others) and consider what she'd be willing to do to keep those around her safe. As we saw in season 3 episode 12, Lena ultimately decided to save Edge from her mother, rather than kill him herself or let her mother finish him off, but can Lena ever truly stay good?