According to theory first developed by Milutin Milanković there is a periodical interchange of ice ages (also called glacial periods) and warm periods (interglacials). The interchange of warm and cold periods is also known as Milankovitch cycles.
When Milanković first developed his theory he stated that cycles are consequance of Earths precession (which lasts for about 26000 years), apsidal precession and change in axial tilt of Earth. Later other scientists included orbital inclination in the theory which helpes explain 100000 years cycles.
This theory does explain many observations made by scientsts (usualy by taking cores of ice or frozen soil from great depths), but it still has its problems and is still under development. This is sometimes reason of conflict between climatologists when discussing human influence on global warming.
For more about ice ages see the lik below.
One should not mix ice age with stone, bronze and iron ages. Ice age is climatological age while stone age, bronze age and iron age are archaeological ages. More precisely they divide human technological prehistory in three periods.
Also we live in geological epoch called holocene which began around 12000 to 11000 years ago and is considered to be intergalcial age. Which would mean we live in warm period and not in ice age.
there were few noted ages pass before "ice age" like stone, iron or metal actually this ages signifies the special implements/tools man use to survive. but when you speak about era, there are a bunch of era before and after us.