Possibly, because the Child Status Protection Act can freeze her age while the petition is pending and adjust for visa availability, but the protection has conditions and a long wait can still exceed it. Her age should be modelled at filing rather than assumed safe.
Model the child's age against the whole timeline
Derivative beneficiaries of an EB-5 petition are the investor's spouse and unmarried children under 21. Under the Child Status Protection Act, the time Form I-526 is pending is generally subtracted from the child's age when a visa becomes available, and the child must then seek to acquire the visa within one year. That rule helps a seventeen-year-old considerably, but it does not stop the clock indefinitely, and it does not help a child who marries.
A family with a child close to 21 should map the expected petition processing time, visa availability for the category, and the interval before consular processing or adjustment, and should be prepared for the possibility that the child needs an independent route. Once admitted as conditional residents, the spouse and children may work and study freely, unlike TD or E-2 derivatives. The child's own conditions are removed on the same I-829 as the parents' unless a separate filing becomes necessary, for instance after a divorce or the investor's death.