Her parents thought her US citizenship was automatic—it wasn’t, and she wasn’t a US citizen until she was in her 20’s after undoing the mess her parents had gotten her into.
I would guess she wasn’t “natural born”.
No, the problem was that her parents failed to go to the US consulate to register her as an American citizen at the time of her birth. If they did, there wouldn’t be any problem.
She would have been a US citizen had her parents bothered to notify the US embassy or consulate of her birth.
Overseas military bases, consulates, and territories (e.g., Canal Zone) are considered American territory for purposes of determining citizenship.
“I know a girl, born to two US citizens while on vacation in Canada, who was not considered a US citizen.”
That’s not true.
There is more to that story.
Paragraph (c) appears to be applicable to this girl you know. We know by law she is a citizen at birth by this very paragraph (c). There is no denying this IMO.
Now read paragraph (a) and notice that it covers over 300 million people in the United States, including at least 40 previous presidents, you, me and most members of Free Republic. Since we are all citizens at birth including at least 40 Presidents of the United States, a citizen at birth MUST also be a natural born citizen.