You ask why create now instead of later or earlier. Why 15 billion years ago instead of 50 years ago. You use this to say that God must exist, becasue choosing that specific time is not random, but an active, conscious decision.
That is not the case. Random events are real. Chance events are real. The universe may have been created fifty years ago, but 15 billion of our years could still have passed. Just because an event happens does not mean that there was an active decision to do it. COnsider shoving your hand into a jar of marbles, with many colors. Yo do not know which one you're going to get. You only know the probability, which is chance, of what you will get if you know how many marbles and how many of each color. But in the end, the one you get is random. That does not mean that God must exist.
All a man's knowledge comes from his experiences