What event is our chronology from? What is called our era?

Our chronology is based on the estimated date of birth of Jesus Christ.
The time from the first year from the birth of Christ to the present day is called our era.

Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.