Lait was just a girl at one point, one that grew up in the 70's and 80's. In the early years, she was thin, frumpy, had almost excessively long hair, and wore a retainer. She had little to no curves to speak of, and ended up blossoming a little later than her sisters.
While her sisters were this curvy when they were getting into their early teens, Lait was crossing this threshold in her later teens.