ей 16 лет. Но это из-за зелья бессмертия, так она живет уже больше 1400 лет. Вот текст с описания персонажа на самом же Шикимори (на английское описание переключись и увидишь
"It's later revealed in the manga that she is the 16 year old daughter of the emperor's subordinate. 1400 years ago, he was ordered by the emperor to burn the potion of immortality given by Kaguya atop Mt. Fuji. Instead, he forced his daughter who was near death to drink the potion. She has since been searching for a way to reach the moon, meet Kaguya, and then hopefully become mortal again."