Why do I exist? Why does the stuff that light and the planets are made of, exist at all and why not nothing instead? There is no scientific way of answering this question and it might never will be, in any case, can we reach any conclusion at all? I think we can.
The problem always comes down to an infinite regression. Why does the universe exist? If we could answer that with something else's existence, then why would that something else exist? The alternatives would be accepting that things might not always need a cause for their existence or that something can be self-caused, so to avoid that, people have come up with infinity as a final answer.
There is this story in Stephen Hawking's "A Brief History of Time", about a lecture on astronomy done by a famous scientist. At the end, an old lady in the back got up and said "What you have told us is rubbish! The world is really a flat plate supported on the back of a giant tortoise!". The scientist smiled and asked "So what is the tortoise standing on?" and the lady replied "You're very clever, young man, very clever but it's turtles all the way down!"
This story pretty much sums up the various beliefs that attempt to avoid the causal problem with an extension of causes to actual infinity. The problem is that the existence of something from infinity wouldn't provide sufficient reason for it's existence, instead of just nothing. Suppose that a series of turtles exist eternally. Would that explain why they exist? It could explain why each one of them exists, if they depend on each other to exist, but it wouldn't explain why the whole infinite set of turtles exist.
I believe that whatever the answer is, it can't be logically satisfying. If something exists, it means that either something came into being from nothing without a cause, or that something exists eternally without any reason to. If we could trace all existence through it's dependencies to some primary being, without any other being capable of justifying it's existence other than itself, then that being would have needed to bootstrap itself into being, from nothing. I think that the only truly logical scenario is the one where nothing at all exists... and that, we already know is false.