As Kant so clearly pointed out there are limits on what we can know. In this particular question we have a built in bias: we already live in a world in which there is something. In fact, we, the ones trying to answer the question, are something already. We have no basis for knowing about a world in which there is nothing (a contradiction as you point out). This is not a question we can logically answer. Any data about the beginning of our present time is not available to us so no amount of pondering will solve this riddle. Some questions are not answerable.