Edward was impressed, but also more than a little annoyed, when Rosalie showed an unusual amount of self-control for a newborn. Carlisle had always praised his self-control. But that self-control had taken a pretty big hit when he'd quit human blood two years ago. He still wasn't back to normal. Meanwhile here comes along a stuck-up sister he didn't ask for whose newborn self-control is inexplicably strong. He grinds his teeth just a bit every time Carlisle lavishly praises Rosalie's restraint.
But what Edward doesn't see is an upbringing in which Rosalie was trained, from a very young age, to be in absolute control of her body. Perfect posture at all times. Anxious checks in the mirror as often as possible. An arsenal of beauty products, uncomfortable clothing, and accessories. Ruthless control over her eating. A beautiful, sophisticated mask as strong as steel. Carefully practiced expressions, gestures, and phrases for countless situations.
Even Rosalie isn't aware of how many years she's trained for this. Her newborn control might not be magical, but it was hard won in a thousand battles that her omniscient brother will never understand.
