Question:
At what age does fasting become obligatory for a girl?
Answer:
Fasting becomes obligatory (Wajib) upon a girl when she reaches the age of responsibility (Taklif), meaning when she attains puberty (Bulugh). Puberty is determined by any one of the following signs:
Reaching the age of 15 years
The growth of coarse hair around the private parts
The emission of seminal fluid (Mani')
The onset of menstruation (Hayd)
Pregnancy
If a girl experiences any one of these signs, she is considered an adult (Baligh) and fasting becomes obligatory for her, even if she is only 10 years old.
Many girls start menstruating at 10 or 11 years of age, yet some families negligently assume she is still a child and do not require her to fast. This is incorrect because, once a girl begins menstruating, she is Islamically considered an adult and is subject to the obligations of Salah (prayer), fasting, and other Islamic duties.
And Allah knows best.
— Shaykh Ibn Jibreen (رحمه الله)
