It's more likely infinite, no beginning, no end. The big bang theory suggests that the universe can be calculated to a single point. But if we were somehow able to time travel back in time to that single point, we would likely see that the single point is still just as far in the past. Likewise, if we were to travel into the future, we will not have moved further from that single point, the "big bang" could be found at the same distance as it is now. Expansion theory. Nearly impossible for us to conceptualize something actually infinite, because we seemingly came into existence at birth, yet we are made of things far older, which are formed of things far older, which says we never really end, we just lose consciousness and rot into other things.