As I mentioned previously, Earth is estimated to be ~4.5 billion years old (technically 4.54 +/- .05 billion, but I figure what’s .04 billion between friends?). I then doubted the veracity of the information because carbon dating is only accurate for around 50,000 years. Well, I am pleased to say I have learned more. Previously, I described radiocarbon dating, but the nuance I previously wasn’t aware of is that there are other types of radiometric dating, too. Many, really. However, a type called “uranium-lead dating” can be used on stuff (like rocks) that are 1,000,000 to over 4,500,000,000 years old pretty precisely.
The oldest minerals to have been analyzed so far are zircon crystals from the Jack Hills in Western Australia, which are at least 4.404 billion years old. That is near as old as the oldest known solid matter in the solar system, calcium-aluminum rich inclusions (CAIs), which are thought to be 4.5673 +/- 0.00016 billion years old (among the oldest known _things_).
As you can probably infer, the accretion of the earth is thought to have begun soon after the formation of CAIs.