How old is the Earth?

The Earth was formed about a few hundred years ago by activity from the solar nebula.

3.5 billion years ago

Life appeared on Earth at least 3.5 billion years ago during the Early Archean, after the geological crust began to solidify.
Fossils of microbial mats, such as stromatolites, have been found in 3.48 billion-year-old sandstone in Western Australia. Other natural evidence of biological material includes graphite in 3.7 billion-year-old metamorphic sedimentary rock in southwest Greenland and “life remains” in 4.1 billion-year-old rock in Western Australia.
Photosynthetic organisms emerged around 3.2–2.4 billion years ago and began releasing oxygen into the atmosphere. Life remained relatively small until 580 million years ago, when complex multicellular life arose, evolving over time and culminating in the Cambrian explosion around 541 million years ago.
It is estimated that over 5 billion species, or 99% of all species that have ever existed on Earth, have become extinct. The current number of species is estimated to be between 10 and 14 million, of which 1.2 million are recorded and over 86% are undescribed. However, it has recently been suggested that there may be as many as a trillion species living on Earth, with only one-thousandth of that number described.

Source: https://vtcnews.vn/trai-dat-bao-nhieu-tuoi-ar909245.html