Explanation:

Why is BC now called BCE?

Simply put, BCE (Before Common Era) is a secular version of BC (before Christ). CE (Common Era) is the secular equivalent of AD (anno Domini), which means “in the year of the Lord” in Latin. ... BCE/CE have been in frequent use by Jewish academics for more than 100 years

BC and AD are years that are numbered according to the year in which Christ was believed to have been born. See, the period before the birth year of Christ is known as B.C. (short for Before Christ) and the years after His birth are known as A.D (short Anno Domini, and meaning the Year of our Lord).

It's nothing to be confused with, my friend. If you still haven't got it, don't worry. Lemme put it in a different manner. Suppose there's a number line having a zero, negative numbers to its left and positive numbers to its right. Think of the zero as the birth year of Christ, the negative numbers represent the years before His birth and the positive numbers represent the years after His birth (refer to the attachment for a more clear visualisation). The negative side is termed as BC (Before Christ) and the positive side is named as AD (Anno Domini, Year of our Lord).