[Mr. Nobody]

I suppose I missed the chat, as always.
To me there is only one answer: Nothing is outside the universe, like nothing is outside the 2 dimensional surface of a 3 dimensional body if you live in 2 dimensions.
We live in 3 spacial dimensions and the universe exists in 4 spacial dimensions. The age of the universe is infinity as anything else would assign a purpose with beginning and end. A purpose to existence I don't see. The age of this expanding epoch of the universe can be measured and is estimated as approx. 13.7 billion years.