FWIW, Ted says he was a US citizen at first breath, but I suppose that would be difficult for him to know for certain on day 1. As smart as he is, he may have been born with a legal brief tucked in his diapers.
No such thing as retroactive citizenship. His parents could have elected the option not to apply for citizenship. The only reason the statue talks about citizenship by birth is to differentiate it from the naturalization process. The reality is that Cruz was a Canadian citizen at first breath.