Accepting One Theory, Rejecting Another, Hitting A Brick Wall

When a Christian says they accept the big bang as the best explanation for the origin of the universe, but then reject the theory of evolution, it then leads to the question:

What has God been doing for so long?

The universe is approximately 13.7 billion years old. This is beyond reasonable doubt.

Also beyond reasonable doubt is that various species of hominid primates have existed for anywhere up to 2.5 million years, but in order to be as generous as I can to the Christian argument, I will put the figure of human existence on earth as 5000 years.

This means that a Christian who accepts the Big Bang as the accepted beginnings of the universe, then has a theology that says that after creating the universe, God sat around for 13'699'995'000 years waiting for...what exactly?