Ginny had never been selfish - it had been all but beaten out of her after growing up in such a crowded environment. The Weasleys shared clothes - Ginny had occasionally been given hand-me-downs to wear, despite being the only girl in the family (other than her mother, of course). She'd never been allowed to have a selfish, greedy stage, where she declared everything to be hers.
So when she fell in love for the first time, with the Boy-Who-Lived, she had never expected him to be all hers. She'd been so used to having to share everything that she never felt he was hers. She hadn't been all that hurt when he broke it off, and had put it up to her usual detachment from all things that it didn't hurt more. Especially after all those years spent admiring him from afar.
However, she was proven wrong when Cho came into her life after the breakup and media outrage; Ginny's emotions had never felt so strong.
Right then, Cho flipped onto her side, disturbing her idle thoughts. One arm flung itself over Ginny's body. Cho unconsciously snuggled in closer to Ginny, and a smile crept over Ginny's face at this feeling of being needed. Warm breaths caressed the side of her face, and she was almost lulled back into sleep.
Cho chose that moment to blearily open her eyes, looking hardly more awake than she had been seconds ago. She sent a warm smile at Ginny and burrowed her face into the tangle of red hair that was splayed out on the pillow. Cho was slighter that Ginny, who had always been fairly broad-shouldered and tall all her life. Ginny felt a now-familiar sense of possessiveness overcome her, and she pressed herself as close to the half-slumbering girl beside her.
"Mine," whispered Cho, voice hoarse and low after the long sleep she'd had.
"All mine," answered Ginny with a smile, unable and unwilling to get over the joy that came with saying that phrase.