It must be assumed. You cannot have a point B without a point A.
The concept, measurement, and meaning of time depend on what happens between point A and B. Without both, you have no time. A stop watch that you never press to begin cannot do anything regarding time.
God cannot ever have had a beginning so there is no such thing as time (no point A) other than as it pertains to His creating (In the beginning).
And you continue begging the question. Just stop before you embarrass yourself anymore.