From the joint interview with Mugglenet/Leaky Cauldron (July 2005), when JKR was asked about the pairing of Harry and Ginny – (Was it planned?
Well, no, not really, because the plan was, which I really hope I fulfilled, is that the reader, like Harry, would gradually discover Ginny as pretty much the ideal girl for Harry. She’s tough, not in an unpleasant way, but she’s gutsy. He needs to be with someone who can stand the demands of being with Harry Potter, because he’s a scary boyfriend in a lot of ways. He’s a marked man. I think she’s funny, and I think that she’s very warm and compassionate. These are all things that Harry requires in his ideal woman. But, I felt – and I’m talking years ago when all this was planned – initially, she’s terrified by his image. I mean, he’s a bit of a rock god to her when she sees him first, at 10 or 11, and he’s this famous boy. So Ginny had to go through a journey as well. And rather like with Ron, I didn’t want Ginny to be the first girl that Harry ever kissed. That’s something I meant to say, and it’s kind of tied in.