Astronomers believe that Venus is about 4.6 billion years old, the same age as everything in the solar system. Objects in the solar system began forming at the same time after a momentous event that may have been a supernova.
Venus's age can be estimated because of radioactive dating of meteorites. Astronomers look at the percentages of radioactive elements within meteorites and how much these elements have decayed over the years to determine age.
In its inception, Venus was just dust, but the dust combined to create grains that eventually became rocks and then a planetoid. Venus is the hottest planet in the Milky Way and experiences temperatures as high as 870 degrees Fahrenheit.