Unfortunately you are all thinking in trems of millions and only billions of years. New deep penetrating telescopes looking back over 13 billion years have found the standard model is not as absolute as we expected. This means the Big Bang could have been an event that created the rules of our universe not just the mass. This also means mass, speed of light, gravitational constant and many things are slowly changing, Time itself may cease may exist 18548711699200000000000000000000000000000000 years from now (inverse of Planck time). The expansion of space /time results in only a change in our 3 spacial dimensions, if time is expanding then time would last forever and it cannot.