Understanding beginningless

I often see the word beginning-less in Buddhist readings and on this site but how do I try to understand this concept being the ignorant human being I am? - Is it just a metaphorical way to describe a very long time? - Is it like the saying which came first: the egg or the chicken in which the answer ‘doesn’t matter’ since they’re both here in the now? - Or is it what we experience is an illusion created from our ignorance therefore there is no real beginning. Scientists say our universe is roughly about 13.8 billion years old so there is probably a beginning? I am not accepting they are correct but not denying the fact either. I feel like when people use the word beginning-less, they are using it as an excuse to explain something that is “unexplainable” because how can something be beginning-less?Is it futile to try to grasp this concept? Or if this concept is understandable what can I do to see this?