What is “outside” is the future. What is “inside” is the past. We are expanding into the former. We are forbidden by Entropy from travelling into the latter.
Everything ahead of us is of course the future. If I wish to travel to northern Michigan for the weekend, that trip would be considered the future until I arrived at my destination then it would be the present.
In applying the same principle to a universe that is expanding due to a gigantic explosion that occurred at point A (the center of the universe) and all the debris flying outwards, assuming I have enough time to do so, I decide to plan a trip to the outermost piece of debris in the universe. While it will certainly take a long time to get there, lets say I do.
Are you saying that once I reach that outermost piece of rock which will then become my present, I can't go any further?
If I am still alive (which of course I am in this narrative) my venture beyond that outermost rock would then comprise my "present" on a journey into the future, just as every day life is.
So, either the universe is forever and ever and ever, OR there are boundary limits that have only been explained theoretically via mathematical equations.....