Worrying about her sister

Lauren had spent the last two years training at the magical powers she developed after her 18th birthday. Slowly, surely, she was getting some mastery of her new mystical skills. She didn't like having to learn from her mother, who was a harsh taskmaster, but apparently it was paying off because she had some mastery of her new occult powers. Nothing like her mother, who seemingly could do anything with ease (which was very frustrating for the still learning Lauren).

Now though, something had happened. Her sister Vanessa had turned 18. Her mother told her that Vanessa would start to develop magical powers as well. It appeared it was taking Vanessa longer than Lauren, since Vanessa was nearly 19 and Lauren's powers had appeared a few days after she turned 18.

But it was coming. Any day now, Lauren's sister would be every bit as powerful as Lauren. Lauren felt she had to do something now, while she had her sister outmatched. Her mother warned Lauren to keep her powers discreet and secret, but Lauren felt she had to declare dominance now, while she was powerful and her sister was not. The question was, how to use her powers over Vanessa?