The age of the Universe is approximately 13.787±0.020 billion years as interpreted with the Lambda-CDM concordance model as of 2018
We can get an aproximate age for the universe from some cosmological observations.
The Hubble constant or the rate of expansion has not been the same throughout cosmic history. Its actual value depends on cosmic epoch.
The age of the Universe is the time elapsed since the Big Bang.
By the 18th century, the idea that the Earth was millions, if not, billions of years old, began to appear.