I read an article about pirates raiding Egypt from 1287-1102 BCE (or something along those lines, specifics arent relevant to my question) but who decided what year to start counting down from, were records actually kept this way or do people try to create timelines and fit them into it? When they say the copper age in Asia was 4500 BCE and the bronze age was 3500 BCE were they actively counting down on their records as well? Is it the same exact 4500 BCE in Europe? What was Asia counting down for- if it is the case. If its not the case then when did the world get on the same page with what year it is (I know some places still arent but when did the majority)
No. How would anyone have known there was something to count down to if it hadn't happened yet?
These numbers are retro-active. Before the year 1AD, no one was using a calendar that matched those numbers. If you look at old Chinese records, the years are counts within the reign of different dynasties.
For example, the year 1680CE in the West corresponds to Qing Kangxi 19 (清康熙19年). Qing is the dynasty name. Kangxi is the emperor name. 19 is the 19th year of said emperors reign. This is the typical way years were documented. This example if from CE, not BCE, but the system is the same since they didn't have any sense of something happening in 1CE as such. Zhou You 2 (周幽二年) would be 782BCE. Zhou Dynasty, King You's second year of rule.
BC/AD and Christian-centric. BCE and CE are as well, but with the terminology changed to be more religiously neutral, but it's still based on a year related to Christ.
Also, somewhat related: There are a lot of different calendars being used right now around the world. It's the year 103 here in Taiwan right now. So even after Christendom got huge, still not everyone is using that count. If you refer to the Western calendar, you have to explicitly state that that's the case. All the official paperwork is expecting you to say 103, not 2014, and if you write 2014, the clerk will be annoyed with you and then change your number to 103.