It says in my 2015 Old Farmer’s Almanac that “The extent of the known Universe is 38 to 47 billion light years in every direction.”
The almanac’s astronomical data is usually quite reliable, but how can the above be true if the Big Bang was only ~13.8 billion years ago? 
Moved Cafe Society --> GQ.
It’s bigger on the inside.
The age of the universe and its size don’t necessarily correlate 1:1.
Though it makes sense to draw the conclusion that the universe should be 13.8 BLY in size since going faster than c isn’t possible for energy/matter.
However, this isn’t true for spacetime itself. Which our current models show is expanding.
There’s also the Inflationary Period that came just after the big bang, which in just a few zillionths of a second, inflated the domain of our universe far beyond that of what c would prohibit. You can then see that the inflation that happened during this time, pushed our “cosmic horizon” out beyond our grasp, and probably plenty of space and matter along with it.