The answer to this question is not as simple as it may seem. Scientists have not been able to determine the exact age of the Earth, but they have estimated that it is around 4.5 billion years old. This estimate is based on several factors, including the age of the oldest rocks on Earth, the rate of radioactive decay, and the age of the universe itself.
While scientists have not been able to determine the exact age of the Earth, they have been able to narrow down its age range significantly. The oldest rocks on Earth are about 4 billion years old, which means that the Earth itself must be at least this old. In addition, studies of radioactive decay suggest that the Earth is probably no more than a few hundred million years younger than 4 billion years old. Finally, scientists believe that the universe itself is around 13.8 billion years old; since our planet must be younger than this, it further supports an age range for the Earth of 4-4.5 billion years old.
Overall, while we don't know exactly how old our planet is, we can be pretty confident that it dates back billions of years into our cosmic history.