The obligation of hijab on a woman upon reaching puberty

Question:
The questioner (A. A. A.) from Dammam says: When must a girl observe the Shari'ah hijab? The question is: At what age does it begin?

Answer:
It becomes obligatory for her when she reaches puberty, when she menstruates, or when she discharges semen—when she has a wet dream—or when she reaches fifteen years of age, just as it is for a man. A man becomes a man when he reaches the age of discernment; as Allah the Exalted said: [Surat al-Nur: 59]. If he has a wet dream, meaning he approaches a woman and discharges, he has reached puberty, or if he grows coarse hair around the private parts, he becomes accountable, and the woman is the same. Or if she completes fifteen years of age, she becomes a man, and the woman is the same. The woman has an additional fourth condition, which is menstruation; if she menstruates, she becomes accountable.