I would like to ask you about a ten-year old girl accompanied by her father to the mosque to pray "Salat al-Maghrib" she prays with us in the first range. The Imam saw her and said nothing. I want to ask you whether our prayer was correct or not.

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions. The standing of a woman in the same row with men while performing prayers is an abominable act and is contrary to the Sunnah. The rulings regarding women apply to a girl when she becomes nine years old. So, she should stand behind the rows of men. However, your prayers while the girl was in the rows of men are valid. Because the majority of Muslim scholars are of the opinion that the standing of a woman in the rows of men is only Makrooh (not likeable) so, the prayers would be valid according to the correct opinion thus your prayer and her prayer too are valid. Allah knows best.