I've always wondered, and cannot find it in the manuals ... what triggers a GA?
EITHER
Winning a fight with your Unique Unit (for Civs with offensive-UUs, this is probably the easiest GA-trigger; defensive UUs can be trickier; and UUs like the Hwach'a, the Conquistadore, the Carrack, and the F-15 can be a royal pain)
OR
Controlling 1 (or more) GW(s) which alone or collectively matches your tribe's Civ-traits (and which you may or may not have built yourself),
during the same interturn when you complete a self-built GW.
Each GW matches one or more Civ-traits, and thus each will be useful to at least 6 Civs, and possibly more. The traits that match each GW are listed in their individual Civilopedia entries, e.g. "The Pyramids may trigger a Golden Age for IND, AGRI or REL Civs" *
That means that for the Celts (REL+AGRI), Egyptians (IND+REL) or Mayans (IND+AGRI), Pyramids would be the only GW needed for their GA. But for
any Civ with only 1 of those 3 traits (e.g. the Persians!), building/ controlling
only the Pyramids would not be sufficient: Xerxes would also need to build a SCI-GW -- or capture a SCI-GW, then build
any 3rd GW -- to trigger his GA.
*I also have all the GW-traits listed on a multi-page PDF I DL'd from CFC (but I'm not sure if that resource is still available). The GWs are assigned their trait(s) in the .biq, so if you're interested, you can also look them up (or modify them!) via the Conquests Editor.
That's probably why I've had financial issues early in the game ... too many buildings. I imagine, going for a SS, Libraries should be first?
Not a bad plan, especially if SCI! But don't build them all at once. Stagger the builds, starting with your highest-commerce town(s) first. And remember that Libs
only multiply SCI%-spending, so you need to keep that as high as possible to obtain the greatest benefit from them.