re: Who was here first: Asian Native Americans or European Native Americans?

12,000 years ago north asian migration
60,000 years south asian migration

There is some debate about who, exactly, the first peoples in North America were. According to new finds, they came from Southeast Asia and the southern Pacific, and are not the ancestors of Native Americans today. Native Americans supposedly descended from northeast Asia, coming into the continent by a land bridge between Siberia and Alaska about 12,000 years ago. The new finds in Baja would refute that claim. Archaeologists are claiming that the peoples from the Pacific/Southeast Asia region arrived before the Clovis people, about 1,000 years earlier.
Why didn't they come sooner? Anthropologists believe humans could not have gotten further south until the clearing of the Ice-Free Corridor about 12,000 years ago, they had to have a clear route to be able to get to North America. Also, because they were hunter/gatherers, it required lots of time for them to make a long journey.
The land was more varied, the climate more temperate and the species of plant and animal more abundant. It had to be difficult to adapt to new ideas, new ways of doing things, and to learn what new things were and were not edible, but seeing the sophistication of the paleo cultures

National Geographic article