I literally obtained derivative citizenship. I never even took an oath.

https://www.uscis.gov/policy-manual/volume-12-part-h-chapter-4

General Requirements for Automatic Acquisition of Citizenship after Birth

The Child Citizenship Act of 2000 (CCA) amended INA 320 and removed INA 321 to create only one statutory provision and method for children in the United States to automatically acquire citizenship after birth. According to INA 320, a child born outside of the United States automatically becomes a U.S. citizen when all of the following conditions have been met on or after February 27, 2001

• The person is a child of a parent who is a U.S. citizen by birth or through naturalization (including an adoptive parent);
• The child is under 18 years of age
• The child is a lawful permanent resident (LPR)
• The child is residing in the United States in the legal and physical custody of the U.S. citizen parent.

There is no specific order in which the conditions of the law must be satisfied for citizenship, so long as all conditions are met at a single point in time before the child’s 18th birthday.

Although this part is concerning:

A person born outside the United States is presumed to be an alien. As such, the person claiming U.S. citizenship has the burden of proof to establish by a preponderance of the evidence that they have met all requirements for citizenship.

👀

Wikipedia: https://en.wikipedia.org/wiki/Child_Citizenship_Act_of_2000

There are some South Korean Adoptees who never became US citizen because the adoptive parents never applied, which is why this law was passed to make it automatic.