Just cause we have to conceive things with the mind doesn't make things less real, just limited in perspective.You are mistaken.....there is no scientific conclusion that there was a beginning to the universe....only those who support the big bang theory....there is not a scientific consensus on it.. and even then there is no understanding how or why such an event could occur.. Similarly with religion...there is no conclusion that God created the universe....pantheism holds that the universe is the manifestation of the eternal God and only the manifested form is subject to beginnings and endings...
Once again....time is a mental construct...it does not exist outside the mind..... QM and GR and all other disciplines of science are helpful to human evolution, but the sum total of the knowledge will forever fall short of understanding the truth.....for 'reality' itself is not a mental construct...whereas all the theories of man are merely conceptualization to represent that 'reality'...see the difference?
Time is a real issue and can eventually mean the end of energy and a cold universe.
For the most part the elements just go on and in this way, death isn't real, however the destruction of cells is a real thing. Cells have no time and replicate in order to "cheat" death but it is a work around that life utilizes. Time is not on our side and isn't a friend of the universe.