All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.
We ask Allaah to guide you to all that is best for you. We also congratulate you for your keen willingness to obey Allaah Almighty. I say: If you decided to fast the above-mentioned days, including the Day of ‘Arafah, and a valid excuse like menses comes to interrupt that, then you will be rewarded for your good intention as if you were fasting. The fasting of the first nine days of Thul-Hijjah is a great deed of righteousness that the Muslim is highly encouraged to do and abundantly rewarded for.
Allaah Knows best.