Surah Talaq 65:4
Lam is called Nafi Jahad in Arabic, which means total negation. This is what the people of the Arabic language understand. It means they did not menstruate at all. There is no hint there for young girls. The word Nisa is used for women and the matter is of marriage, divorce, and iddat. So, therefore there is no way to think it is for young girls.