"Narcissa was too young at the time. She started her seventh year when you were in your last. And while you and I both look like him, you share more of his personality. I think he saw himself in you and wanted you to provide him with what he wanted. So he pulled away to let mother do her thing, and instead of becoming the perfect pureblood daughter, you were insistent on drawing his attention. You acted out, got detention, failed assignments and then would perform the magic perfectly so as to annoy him. It distracted them enough from what I was doing, anyway. 