Actually, if she was 100 years old, she'd have 2 tails. Kitsunes grow another tail for every 100 years they live, until they have 9 (They're born with 1). If I remember correctly, once they have 9 tails, they lose a tail every 100 years till they have 4, which makes them a heaven type fox. So this Ran is anywhere from 1 to 99 years old.