She took apart her old national age - group record of 30.02 seconds in the process .
Was the first 9 - 10 - year - old swimmer to go under the 30 - second mark for the event .
She took apart her old national age - group record of 30.02 seconds in the process and was the first 9 - 10 - year - old swimmer to go under the 30 - second mark for the event .