Well, by definition, a "Native" American would be the original inhabitants of the land- who are you claiming are the "truly native" Americans?

The first peoples who lived in America came from Asia through Beringia, a mass of emerged land that today is Bering Strait. That was about 15.000-20.000 years ago and before that there weren't any humans living there. Most of the pleople know as Native Americans are descendants of those first peoples.