Rasulullah (sallallahu ‘alaihi wasallam) said to his beloved daughter, Sayyidah Faatimah (radhiyallahu ‘anha), on the Day of ‘Eid, “O Faatimah! Stand and witness your sacrificial animal (being slaughtered), for verily you will receive forgiveness for every sin the moment the very first drop of its blood is spilt. Behold! Its flesh and blood will be brought (on the Day of Qiyaamah) and placed on your scale, (multiplied) 70 times (in weight).” Sayyiduna Abu Sa‘eed (radhiyallahu ‘anhu) asked, “O Rasul of Allah (sallallahu ‘alaihi wasallam)! Is this (virtue) for the family of Muhammad (sallallahu ‘alaihi wasallam) alone, for they are indeed worthy of virtue which is bestowed to them alone, or is it for all Muslims in general?” Rasulullah (sallallahu ‘alaihi wasallam) replied, “For the family of Muhammad (sallallahu ‘alaihi wasallam) especially and for all Muslims in general (as well).” (At-Targheeb wat Tarheeb vol. 2, pg. 154)
For a woman to witness the slaughter of her qurbaani animal is definitely meritorious, as it was the wish of Rasulullah (sallallahu ‘alaihi wasallam) that his own dear daughter witness her animal being slaughtered.
As meritorious as it may be, however, this action will NOT gain us the happiness of Allah Ta‘ala and His Rasul (sallallahu ‘alaihi wasallam) if, in the process, we blatantly trample the laws of Deen. How sad if an action undertaken to secure the pleasure of Allah Ta‘ala, instead earns us the displeasure of Allah Ta‘ala! It is thus absolutely essential that due attention be paid to aspects such as purdah/hijaab, intermingling of sexes, etc.
Let it not be that the Day of ‘Eid, a day of happiness, a day meant to take us a step closer to Allah Ta‘ala, actually takes us 10 steps away from Allah Ta‘ala!!!