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.
First and foremost we ask Allah to make you stay firm on this religion and to open your heart to Islam, and strengthen your guidance to the straight path.
We inform you that the first day of Dhul-Hijjah is Friday 23/01/04. However, this could be different from the calendar, it could be one day earlier or one day later; this depends on the sighting of the moon, according to Islamic principles, in confirming the starting of the month.
You can find out by asking some Islamic centres or checking some Islamic websites which announce the starting of the month of Dhul-Hijjah.
With regards to when one can start fasting; it is permissible to fast from the first day of Dhul-Hijjah until the Day of Eid, when one has to break the fast, as it is forbidden to fast on Eid day according to the consensus of scholars.
Allah knows best.