What is the ruling on a mother preventing her daughter, who has begun menstruating, from fasting in Ramadan, under the pretext of her young age?

When a girl menstruates, she has reached puberty and becomes obligated to perform prayer, fasting, and other duties. No one is permitted to prevent her from fasting. If someone does so, they have sinned and must repent. Similarly, it is not permissible for the girl to obey anyone in abandoning fasting. If she obeys her mother, she must repent and make up the fast.