I-129F question 10 - question

[MisterT]

Hello everyone. I am preparing to submit my petition package for K1, so that I can be with my fiancee soon.
On the citizenship question, I am confused. I was born in Germany to a US father and a German mom.
I was issued a "certificate of birth abroad"(of a US citizen) by the US embassy when I was 18.
Therefore I am not born in the US and never received a certificate of naturalization. So how do I fill out this part of the form?
Any help would be greatly appreciated.

[JustBreathe]

Hello everyone. I am preparing to submit my petition package for K1, so that I can be with my fiancee soon.
On the citizenship question, I am confused. I was born in Germany to a US father and a German mom.
I was issued a "certificate of birth abroad"(of a US citizen) by the US embassy when I was 18.
Therefore I am not born in the US and never received a certificate of naturalization. So how do I fill out this part of the form?
Any help would be greatly appreciated.

That is a pretty deep question. I would advise to contact USCIS and request guidance.