An I-130 is approved for a preference relative and the relative is given a priority date. Visas are provided to preference relatives according to their priority date and on a first come first serve bases. There are limited situations when a preference relative is granted permission to enter the United States before his or her priority date becomes current.
Preference Categories are as follows:
• First preference: Unmarried, adult sons and daughters of U.S. citizens (adult means 21 or older).
• Second Preference (2A): Spouses of green card holders, unmarried children (under 21) of permanent residents.
• Second Preference (2B): Unmarried adult sons and daughters of permanent residents.
• Third Preference: Married sons and daughters (any age) of U.S. citizens.
• Fourth Preference: Brothers and sisters of adult U.S. citizens.