The term beginning refers to time. Unbelievable as it might sound Einstein proved mathematically beyond doubt that time is not a constant. People in different positions will observe the length of time differently. The only constant in our universe is the speed of light. The faster you travel , the slower time appears to pass and at the speed of light time ceased to pass. A second would last an eternity. Time is also slowed down by gravity. In the graviton field of very large or very dense objects time seems to slow down to an observer who is outside this gravitation field. In the gravitation field of a black hole ( the most dense object imaginable) a second will last an eternity. ( to an outside observer , observing an object entering a black hole, it will appears as if time stopped). BUT to the observer in this strong gravitation field time would appear to progress at the normal rate.

What is the answer than to the question "was there a beginning?" I doubt if we will ever know the answer especially at our present point of observation. Our universe might have a beginning and a possible end, but what exists before it . Light is energy ( as is everything we observed , including ourselves). Where did energy originate? Was that the beginning?

My conclusion is that with our present knowledge and from our point of observation we must except there never was a beginning and that there never will be an end.