This question emits something from our entire experience as human beings: our cars had a beginning, our houses did not always exist, our lives have a starting point, even the earth itself we read in Genesis 1 & 2 of how that there was a beginning. We can trace everything about ourselves back to some starting point. So for us to consider something that didn’t have a beginning really stretches our thoughts and pushes us beyond our own experience.
But we read in Psalm 90:2 that “before the mountains were born or you gave birth to the world even from everlasting to everlasting you are God.” This is saying that “everlasting past and everlasting future you are God”. Psalm 93:2: “Your throne is established from of old. You are from everlasting.”
Pointing back that God had no beginning, He never became a being. See also Psalm 102:25-27. God did not have a beginning. He has always been and always will be.