A while back, I read a comic (DC, I think) in a compilation that I'd like to find again. I think it was one issue. Even though this character could have more comics, I'm just looking for the one issue. This was ages ago, so my details are very fuzzy.
The story starts with a girl with long black hair in her bedroom with a friend. Her friend jumps on the bed, and the girl flies around it. I think they discuss how she gained superpowers. She has a yellow star she wears on her chest that gives her her powers. I think her superhero costume is red with yellow. To the best of my memory, I think it's Batman who introduces her to the superhero world. Her mom knows about this. The girl ends up getting shot or something, and the yellow star shatters. Her mom is later crying over a scrapbook, saying how sad everything is. The girl says "It's not like I died or anything Mom - I just don't have powers anymore." She goes to her room, her hair in a towel, and sees her superhero costume on her bed with a note from Batman. She smiles and looks out the window, and I think there's a silhouette of Batman.