Sheikh Sharaf al-Sharîf, professor at Umm al-Qurâ University
Women are allowed to perform congregation prayers together at home. Their imam will stand in the middle of the row.
It was reported that `Aishah and Umm Salamah used to stand in the middle of the row of worshippers when they acted as imams for other women in prayer. Umm Salamah’s statement on this matter is conveyed by al-Shafi`î in al-Musnad 6/82 and by Ibn Hazm (3/172).
Standing in the middle is more preferable, but if the imam stands in the front, this is also permissible.
If only two women are praying together, the other woman has to stand to the right of the imam. Standing in front of her or behind her will be illegal. This is the same ruling as the one for two men in prayer.
And Allah knows best.
Source: Islam Today