We will say that you shall begin in the city of Relkath's Foot in the country of Algarond. The city is on the edge of the Yuirwood. This is on the continent of Faerun, the largest continent in the Forgotten Realms. This is where you will begin.
First off, come up with a reason why you are in Algarond in the first place. Maybe you are there just to adventure, or to meet women. Or just to get gold. Or, to adventure to find gold and women. Either way, come up with a brief history, as well as where you would like to begin...in an inn, at a temple, out on the street.