Logic is a useful tool for finding truth but it doesn't always work everywhere- especially when it goes into this arena. There's a lot of other neat truth tools that we all use every day (senses, tradition, intuition, pragmatism, etc.) but (like you) I personally have never had much use for the first-cause 'proof'. Carl Sagan put it well when he we suggested that if all we want it is a first cause, then we can just save ourselves a step and say the 'universe' itself is the first cause.
The problem that I see with time and space is that the concepts are significant only if something is happening. It gets worse considering the fact that both are relative. [big word alert-- small words available only upon request] If our observations are correct, that the course of time slows asymptotically back to the big bang, then we could argue that before the big bang time went backwards (?!).
I think I'm going to need more than one cup of coffee this morning before I can think about cause and effect with a reverse time flow.
I think addressing the problem is beyond the range and scope of my mental abilities. But I am not going to jump to the conclusion of a supernatural being creating the universe. Actually if I was prone to that type of thinking, I would expect several supernatural beings to be involved and not just one.
I am having a problem right now deciding when I head out on the briny at 5 AM in the dark into that cold easterly wind , whether I should get greedy and make a try for the haddock on the north shoals in 100 feet of water or go directly to the east and fish 240 feet of water where I know the haddock are located.
If I get on them in the shallower water I will get twice as many fish in the boat in the same period of time as fishing the deeper water. I think I can get that problem resolved before daybreak. But supernatural beings and the origin of the universe still stumps me. - tom