And even YOUR ancestor came here from somewhere else. The "native Americans" also came here from the old world - across the land bridge on the Bering straits. Granted it was maybe 30,000 years ago, but they still came from somewhere else.
Everyone on this continent traces their ancestry to somewhere else. Originally there were NO humans on this continent.
Literally everyone in the Western hemisphere descended from immigrants. Everyone.
That literally is true of everyone on every continent if you go back far enough. The real point that gets obscured -- no, denied -- by the "we're a nation of immigrants" assertion is this:
Ever since the advent of city-states (precursors to nations) birth within the borders of a state was the very definition of being a Sumerian, Egyptian, Judean, Babylonian, Athenian, Roman, later French, English, Chinese, American, etc.