How so? ... Only if you're willing to concede that God does not exist.
Iacchus, why does this change the situation a bit? Once you let in one entity for which there is no evidence, in order to attempt to explain something, what is to stop you from admitting another, and another, and turtles all the way down? You are trying to infer from our mere existence that god must logically exist to have jump-started the whole thing. So, this god is both inferred from our existence and allegedly the cause of same. Where have we heard this before?...ah, yes, circularity!
So, the logical argument you are attempting is bankrupt. You are left with either simply assuming the existence of a god (and admitting it is an assumption which is backed by neither logic nor evidence) or finding some evidence. The latter will be difficult, as you are attempting to find evidence for something which is outside the knowable universe. Good luck with that.
So it is not so much the notion of "conceding that god does not exist". Frankly, your attempt at logic renders any god irrelevant, so our default position is "no evidence for a god". It is not the same as conceding that god does not exist, but I don't think you'll be particularly happy with it either.
Once again, Iacchus, the honest answer is that we do not know, because we have no evidence, much at all about the opening moments of our universe. And neither do you. And none are claiming "something came from nothing", because that is more knowledge than we have. (It may be the case, though, that you are claiming that god came from nothing. That is something you will have to work out for yourself.)