Many if not all human societies have origin myths and they differ greatly.
Several years ago a San Francisco-born-and-raised woman told me she is a materialist.
An hour ago a woman who was raised a Jehovah Witness and has left that faith told me the Big Bang story grew from a human need for a beginning. I agreed.
Can you wholeheartedly accept that the universe had no beginning, that it has always existed?
Yes I can Tom. You could throw a stick at a crowd of Cosmologists and find a different theory being spouted. The weight of evidence points to a beginning but not enough to be certain.
Humans are all born and have beginnings. The Big Bang is an event that created the universe we live in and may have come from an all existing multi universe.
Scifi authors do it very well sometimes!
I don't know enough to accept *anything* wholeheartedly.
But, I must say that, considering the incomprehensible size of the universe and Humanity's concomitant insignificance / ignorance of "what is," - and at the risk of sounding like Captain Obvious - I can readily accept that the universe either always has or has not always existed. Until it's proven, Schrodenger's cat is still in that damn box. :)
I can't explain the mechanism of an airplane or a computer, but I know they are man made. There are set principles that, once met, give machines and systems. The same applies to universe. A number of principles produced it at a certain time--beginning--and some other principles will end it at a certain time. I'm not too weak to be infatuated with sweet, soothing and short-sighted biases like "if you can't understand it, it's because God hid it away from you!" though. Time will tell anyway. Remember, some time in history, almost everybody believed Malaria was caused by evil spirits or bad air [mal-aria]. Not today--unless you're a true sheeple!
I have no problem accepting that the universe has always been.