No, it means God is necessary, if you assent to propositions one and two.
1. Everything that begins to exist has a cause
2. The universe began to exist
3. Therefore the universe had a cause.
As per this argument, there *must* be an immaterial, timeless, and very powerful cause for the universe. There are a few more assumptions at play that get us to "God", such as things that cause other things exist, but by and large, the cosmological argument gets you to a necessary cause for the universe.
Now, that being said, my reformulation of the argument does not have such strong or clear bonds of necessity, partially because I was trying to anticipate the objection "but what caused God." And technically, the cosmological argument proves the existence of
at least one god, rather than a singular deity, since the being that created the universe could have had a cause itself, and that cause could be eternal and uncaused. Nevertheless, I don't think you can escape the idea that the cosmological argument proves that there is at least one God without finding fault with the first premise, which, I confess, is not impossible to do (or the second premise, but people are usually disinclined to argue with science, for some strange reason
).