The second question is easier to answer: Yes. The Nahua and Maya have their roots in the Mesoamerican cultures that come from the Olmec. They share similar mythologies and have economic pursuits that appear similar at times and places. The Classic Maya was contemporary to the civilization of Teotihuacan while the Post-classic emerged and thrived during the rise of the Nahua speaking peoples like the Mexica (Aztec). See Arthur Demerest's work on the Maya to see how they developed during these two distinct things periods.

As for your first question, I would argue that culture and background are factors. I'll assume that you are from North America/USA. There are/were more Mesoamericans arriving to that part of the Americas than Andeans. If you lived in South America you would see and hear much more about the Andean cultures and the Inca in particular than if you were in North America where more people have connections to the Mesoamerican civilizations than those in the Andes.