“Well, we’ll have to fly, won’t we?” said Luna in the closest thing to a matter-of-fact voice Harry had ever heard her use.
“Okay,” said Harry irritably, rounding on her, “first of all, ‘we’ aren’t doing anything if you’re including yourself in that, and second of all, Ron’s the only one with a broomstick that isn’t being guarded by a security troll, so –”
“I’ve got a broom!” said Ginny.
“Yeah, but you’re not coming,” said Ron angrily.
“Excuse me, but I care what happens to Sirius as much as you do!” said Ginny, her jaw set so that her resemblance to Fred and George was suddenly striking.
“You’re too –” Harry began.
“I’m three years older than you were when you fought You-Know-Who over the Sorcerer’s Stone,” she said fiercely, “and it’s because of me Malfoy’s stuck back in Umbridge’s office with giant flying bogeys attacking him –”
“Yeah, but–”
“We were all in the D.A. together, said Neville quietly. “It was all supposed to be about fighting You-Know-Who, wasn’t it? And this is the first chance we’ve had to do something real — or was that all just a game or something?”
“No — of course it wasn’t –” said Harry impatiently.
“Then we should come too,” said Neville simply. “We want to help.”
“That’s right,” said Luna, smiling happily.
Harry’s eyes met Ron’s. He knew that Ron was thinking exactly what he was: If he could have chosen any members of the D.A. in addition to himself, Ron, and Hermione to join him in the attempt to rescue Sirius, he would not have picked Ginny, Neville, or Luna.

Harry Potter and the Order of the Phoenix – J.K. Rowling