The Mayan and the Aztecs were roughly at a similar level of development as ancient Sumer or Babylon: good agricultural practices, irrigation, astronomy, elaborated culture, rich mythologies, very basic metallurgy, early state structures, etc.
Sumer and Babylon were great civilisations whose legacy can still be traced today. The same is true for the Maya and the Aztec. Had you visited any of them in their prime, you would have been awed by their skill and sophistication.
And yet, think of everything that happened in Eurasia between Hammurabi and Columbus, and you will get a sense of how wide the gap was when the two worlds met.