According to the standard theory, our universe ... all of those BILLIONS of MASSIVE stars ... sprang into existence as a "singularity" ... a particle of infinite density smaller than an atom ... around 13.7 billion years ago that - POOF - magically appeared out of nowhere. Do you have any problems with that postulate?
I don't 'believe' anything. I go wherever the evidence leads. The evidence for an expanding Universe is very strong. An expanding Universe an ever smaller Universe in the past. It may not have began as a singularity, which is the standard model. There are other models and other possibilities. It is not known how the Universe got started, or even if it did. It may be cyclic, a part of a larger system or just a regular feature of quantum fluctuations....which are known to produce virtual pairs, which may become actual pairs of particles in the presence of gravity.
The essence of all this is; we do not know how the Universe began but the evidence does provide us with possible models based on the evidence.
It is a mistake to say, we do not know how the Universe began therefore it has to be created by God, which is explains nothing and is a logical fallacy: the God of the Gaps.
''Yet you ridicule the idea that our universe could have been created by an "Almighty".''
There is no evidence for the proposition of an 'Almighty' - it's merely an assumption born of desire, hope and fear. It's also the god of the gaps fallacy.