you are not thinking straight. there is always a starting point. the starting point must be self-existent.  if you say aliens created humans then where did aliens come from? you must have a starting point. but you will soon realise that a starting point is either self+existent or it has a starting point itself which leads to the same question what's it's starting point. the only logical answer is self+existence. because you cannot go from nothing to something because nothing is no thing, it's not anything. so there must have always been something (self-existence).
Australia