Last month I adopted my step-daughter. Her biological mother is my wife. Both are Permanent residents of the US and have been here for almost 3 years. They will both be eligible for their naturalization in less than 2 years. However, since I just adopted my step daughter, can I now file the n-600 Application for Citizenship and Issuance of Certificate under Section 322?

It is a little confusing, the n-600 form says the purpose of the form is "For a child who regularly resides abroad to claim U.S. citizenship based on parentage". However, she doesn't regularly reside abroad. She resides here in the U.S. for the past 3 years.

Please help me understand this.

The instructions I read state that the N-600 is applicable if the child was born outside the United States and legally admitted to the U.S. as a permanent resident and that the child was either the biological or legitimated child of a U.S. citizen parent prior to reaching the age of 16.