Why she is so awesome.Edit
|“||Most of you already know I'm awesome, so I don't really need to get into depth. Anyway, I'm awesome.||”|
Her name is Kara Zor-El. She came from a planet from yours, she journeyed across an ocean of stars to reach you and look there! Here comes her fist in your face. If she's not feeling like reaching your sorry self, she'll zap you with a heatray or encase you in a block of ice. It helps that she has super hearing and X-Ray vision. Even if by some miniscule chance she didn't win and take you off to jail, she could simply fly around Earth a few times to go back in time and try again, so it's clear it's impossible to ever cause trouble and get out of it when she's around.
Even if she's actually older than Superman himself and was around in the days when his diapers weren't changed by Lois Lane, by virtue of her awesomeness she looks way younger than he ever will. When her parents sent her away on a rocket as Superman himself was, it happened to get sidetracked by a meteor, so she arrived on Earth years after he did. A brief period of getting used to her new planet, meeting up with her cousin, training with Wonder Woman, she once went around undercover using the alias of Vanellope both for the purpose of fun and to spy on her enemies, and other ordinary events was interrupted by some troubles forged by Darkseid. After he was sufficiently taken care of, she became Supergirl. That is but a mediocre snippet of her awesome origin story.
Plus as a blonde it gives her super intelligence a super boost.
Besides her aforementioned relations, Supergirl has a super cool brother by the name of Billy (no other super powers at the moment), who enjoys killing things.