Frohms first appearance in an international tournament was the finals of the 2012 UEFA Women's Under-17 Championship where she played as the main keeper in the semi-final role against Denmark before stopping penalties from Chloé Froment and Ghoutia Karchouni in the final to give Germany the Under-17 title and also gaining a spot in the FIFA U-17 World Cup. Later that year she was chosen as the main goalkeeper for Germany at the 2012 FIFA U-17 Women's World Cup where she would play in all six of the matches as the national team finished in fourth place.