Acceptance.  That is the name of this issue and the story shows us that Supergirl, through all of her trials and tribulations up to this point in the series, has accepted her destiny.  She fianlly realizes her role and responsibility.  She finds out why her parents realy sent her to Earth.  She finds out just how important she is.  For so long she has felt like a second rate Superman, or like just another Earthen hero.  Kara didn't feel that she belonged and she was right.  She now realizes why, and just how important her uniqueness is.

This story with her emotions and Supergirl's need to 'find herself' has been the theme of this entire series run.  I am still looking forward to seeing her act like a grownup eventually, or at least I hope the series shows her that way one day!