If you think about it, having a GA while still in despotism doesn't take full advantage of the GA. Under despotism, you are not allowed to use the third food/shield/gold that might be produced on a tile being worked in one of your cities. Golden Age adds one shield and one gold to all tiles. Most of my citizens, 3/4 or more, are producing exactly 2 shields and half will collect exactly 2 gold. If I enter a GA in despotism, I get less than 25% of the shield bonus, and only half of the gold bonus. For this reason, I try to avoid an early GA. The problem is that one half of the civs have an ancient UU, so early war means early GA. The religious civs have a disadvantage here too, as the 3 earliest Wonders could trigger GA if built by religious civ. I think that the rules governing golden ages should be changed to prevent an effective 30% GA.