Well I suppose strictly speaking there could also have been "something" "forever", whatever either of those two things means. But if you take the argument from first cause even remotely seriously, then all it establishes is that something exists that is capable of creating itself. There's no particular reason to suppose that this something isn't the Universe.
But anyway. The real mistake in the question is in assuming that there has to be an answer, or at least that there has to be an answer *now*. Barely a century ago, we had no certainty that atoms even existed; now we have already begun to probe and understand the building blocks of the building blocks of *those* building blocks. In the other direction, the "Universe" was the same thing as our own Galaxy, and now we know of billions and billions of others. Our understanding of the very large and very small has grown by several orders of magnitude in barely 100 years. Who's to say what will happen in the next 100? And beyond that? There's loads of time left to figure out even partial answers to these questions, as opposed to giving up and assuming that God did it.
I would never pretend that Scientific endeavour truly touches upon the religious. By definition, a supernatural being who created the Universe and who wields ultimate control over its rules is immune to testing. But the reverse is also more or less true; Religion has nothing meaningful to say on questions scientific, much as it may wish to pretend otherwise.