When did the course of the Baltic Sea coastline finally form?

The Baltic Sea is one of the largest brackish inland seas by area, and occupies a basin formed by glacial erosion during the last few ice ages. It is about 1,600 km (990 mi) long, an average of 193 km (120 mi) wide, and an average of 55 metres (180 ft) deep. The maximum depth is 459 m (1,506 ft).The current course of the shoreline was formed about 2 thousand years ago.