Praise be to Allah.The fact that you have concern with the blessed month of Ramadhan, are questioning it's arrival, and anticipating it, is very wonderful. It indicates that you are affected by this great Islamic worship, which consists of abstaining from food and drink, and sexual intercourse from fajr (the break of dawn), until maghrib ( the sunset) during the day of the noble month of Ramadhan.
As far as it's appointed time, my dear respected questioner, the laws of worship in Islam are scheduled according to proof which is clearly traceable and detectable. The evidence which is seen is not estimated. This entails the sighting of the moon, which indicates that the month of Ramadhan has begun. So, if we see the new moon, or it is established that someone amongst us has seen the new moon, then it becomes obligatory on the entire Muslim community to fast every day of this month, until we see the new moon for the following month of Shawwal and know that therefore Ramadhan has ended.
The month of Ramadhan on the Islamic calendar could be 29 or 30 days depending on the sighting of the physical proof, which is the new moon. According to the Christian calender, the approximate time of Ramadhan this year would occur on the 30th or 31st of December 1997.
In order for your fast to be correct and accepted, you must first enter Islam by testifying to Allah's Oneness and believing in the Prophet and following the laws of Islam. We would be happy to see you living a happy life with strong faith, and good years to come, spending them inspired by Islam. We ask Allah to protect you and guide you along.