It's well into the billions as far as I can tell and the scientific consensus is that it most certainly did have a beginning, a very sudden one. The actual sphere is only slightly younger then the rest of the universe but less then 10,000 years ago was covered in water and utter darkness, void and without form. Biological life was created exactly as described in Genesis in a matter of days and on the days of creation it didn't take all day to do it.
Don't get me wrong, I am under to compulsion of any kind to accept an old earth or cosmology. I just realize that the Scriptures are silent on that particular point, both as canon and as understood literally from the narratives as literature.
Hope that helps to clarify, feel free to ask any follow up questions that occur to you.
Grace and peace,
Mark