Don't worry about ages. I personally only take very careful on era points when 1. I have a ton of faith, under such circumstances I have to get to monumentality to make full use of the faith. However if the faith comes from Holy Sites, monasticism+Jesuit is better. So I wish to get into either dark or golden age, but not normal age. 2. I have a ton of Harbors, free inquiry gives a lot of science so I must try my best for a golden age. Otherwise you don't need to care. Being normal or dark will not hurt you since even if you get to golden there's no severe bonuses. Twilight Valor on dark age is strong but not game-changing. Same for the district+1 culture golden age.