I wish you'd posted this in religion or Science and I'd have picked it up earlier.
Don't know if you'll read this but anyway.
The Cosmological argument is usually put forward by people who have little idea about science - certainly about modern science.
It argues that an effect must have a cause - nice idea, 100 years outdated. Quantum mechanics has shown us plenty of effects that are truely random. Chaos theory has shown us how tiny random effects can affect the every day.
These people try to apply the physics of the every day to the extremes of the instants of creation. It's a bit like thinking no car can go faster than 100 mph because you've only ever seen a VW Beetle!
It's also shot because it assumes it's own idea of scientific rationalism (every effect must have a cause) and then promptly abandons it to ascribe God to the first cause.
You may call that first cause God - that does not make it a personal all powerful deity - it could be a quantum fluctuation
However that's a bit of a sideshow - The cosmological principal is attempting to use science to justify ideas arrived at by faith.
Does the fact that the CP's nonsense from a modern scientific perspective deaden the heart of one believer? is there anybody who's faith is pinned on this idea? I doubt it.
It's mearly a debating tool used to attempt to undermine science based athiesm.
If you go down the scientific route check out Karl Popper and the principal of falsifiability.
best of luck