The Earth itself is about 4.6 billion years old.
From Steve Jones' "Darwin's Ghost," we have on page 195 ...
"The evidence comes not from our own planet, but from its satellite. The Moon flew off its parent after a giant impact. Because it stayed small, cold and undisturbed it gives a better picture of the past than its parent. A quick trip by the Apollo XI mission was enough to date it."
I have yet to find any evidence that anyone knows exactly how old this earth literally is. I can accept the number in billions of years, but I would not stake my life as to the literal number.
I agree this earth is very very old, but I do not put much credibility in any who claim a specific age. Most especially when an 'age' of anything is then used as claimed evidence for the fairy 'tail' of evolution.