Is a girl who has not yet reached puberty – who has not menstruated – due to medical reasons, held accountable, and do the rulings regarding adults apply to her?

A woman reaches puberty upon the occurrence of one of the following signs: menstruation, growth of coarse hair around the pubic area (pubic hair), emission of semen, or reaching fifteen lunar years of age. When any of these signs appear, the woman is considered an adult and accountable for religious obligations.