She's Kara Danvers aka Kara Zor-El. She doesn't let people know that she's Supergirl.
from Krypton, a planet that was destroyed. she came to Earth to protect her cousin Kal-El,who is Superman.but she arrives 10 years later than Supergirl. She was adopted by the Danvers family and grew up as a human girl. She work as a personal assistant and a reporter for CatCo Worldwide Media, and as a superhero and a D.E.O. agent for National City.she has many enemies who want to harm me.She's 20.