Will my child age out?

The child's age on the day a visa became available, less the days the petition was pending. It's INA 203(h)(1), the Child Status Protection Act of 2002. A CSPA age under 21 means the child still counts as a child for the parent's green card, as long as the child is unmarried and sought to acquire permanent residence within a year.

It's the petition the green card rests on. For a child on a parent's work-based case, that's the parent's I-140. For a family case, it's the I-130. It's the days from USCIS's receipt date to its approval date, administrative review included. If the parent's case moved to a second I-140, the second one counts, even when the priority date came from the first.

On the later of two days: the petition's approval, or the first day of the bulletin month whose Final Action Dates chart shows the priority date current. That's USCIS's rule for I-485s filed on or after August 15, 2025. For I-485s filed before then, USCIS uses the chart it named for filing that month, which was often the Dates for Filing chart.

Filing the I-485, submitting the DS-260, or paying the visa fee, within a year of the day the visa became available. If the visa stops being available before a full year passes, a new year starts the next time it's available. A full year of availability with nothing filed ends the protection, unless USCIS finds extraordinary circumstances.

Once the child has filed and the visa had become available by the Final Action chart, the age is fixed through the decision, and USCIS holds the application until the date is current again. If the child filed early on the Dates for Filing chart, the age is fixed on the first day the Final Action chart reaches the date.

No. It's the arithmetic in the statute and the Policy Manual on the dates you enter and the bulletin archive. Marriage, extraordinary circumstances, which petition the case rests on and how USCIS read a given month are questions for the attorney who files.