Nanako was still in her senior year of university. She was twenty-two years old and she was about the same age as Aurora.
As for Jasmine, she was about the same age as Charlie.
Hence, Jasmine was four years older than Nanako.
It was only reasonable for Nanako to call Jasmine her elder sister then.
But Jasmine was still very flattered because of Nanako’s attitude.
After all, Nanako was now the head of the Ito family, which was the largest family in Japan. The strength of the Ito family was a