I loaded up a save from a week or so ago to keep plugging away. I noticed I after trading a bunch of techs for cash (too cheaply I might add) that I am now in the age of war even though it is only turn 45 and I don't have nearly probably 1/3 of the techs on the first age. Also, military invasion is available to me even though I still don't have the tech before it, military specialization.