Ok, about iron working... What I read a while ago is that assyrians were the first to develop iron working, however, they only had scarce source of iron(coming from meteorites mostly). They traded the technology at the city of Kanesh, and the Hittites started using iron too, but more quickly. However, what little is known is that many civs, even Hittites, were reluctant to use Iron. Even if more resistant, it took MUCH bigger forges and heat to smelt iron, and required too much work compared to bronze, and was often of bad quality(coming from meteorites). However, when the 'Sea People' invaded the shores and settled in as the Philistines, they destroyed all trade routes with spain and britain, cutting off most supplies of Tin. Because of that, most civs switched to Iron.
That's what I read, I'm not 100% sure it's accurate however.