If my father is from Guatemala and i was born in the USA are am a citizen?

If you were born in the United States, you are a US citizen, regardless of your father's nationality or citizenship. Birthright citizenship is a fundamental principle of US nationality law, established by the Fourteenth Amendment to the US Constitution. According to this amendment, "All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside."

So, since you were born in the United States, you are a US citizen, even though your father is from Guatemala.