Energy can not be created or destroyed by natural means. So that energy has always existed??? well always existing with no source still blows my mind.
Of course a god that can creat a universe is just as much of a tall tale as well. The genesis of the universe is where I hold some possible belief that there might be a creator. If science comes up with a plausible explanation I might change my tune.
So the answer should be, "I don't know" - and leave it at that.
There are people who claim to have had personally spoken with a diety, seen cities shattered from the sky. I believe it is myth and legend typical of humans but there is a claim that god is real and has made himself evident.
My answer is I don't know, I lean towards god being myth of the superstitious but I can not off hand say that there is no god.
PS an atheist, at least most of the atheists here make the claim there is no god and violently defend that position many want to convert believers and they appear to be on a religious crusade to prove their point. Not that atheists simply don't believe in god, it is much more direct than that.