Her eligibility as a derivative depends on being your unmarried child under 21 at the operative moment, with age protection applied on the facts of your case, never a promised outcome. A twenty-year-old is not too old; the risk is what her calculated age is when a visa number becomes available.
Track her position against visa availability, not project milestones
Ask counsel to map two timelines side by side: her birthday against the priority date and the Visa Bulletin, and separately the project's revision schedule. Chargeability usually follows country of birth, so a Canadian address or passport alone does not fix her queue. If she marries, or her calculated age reaches 21, her derivative claim can end — a decision worth understanding before it happens, not after.
A spouse and unmarried children under 21 may derive, subject to individual eligibility and age review; gather passports, civil-status records, and consistent case identifiers for each person. On approval the investor, spouse and unmarried children under twenty-one receive conditional permanent residence for two years, and the conditions are removed by filing Form I-829 with evidence that the capital remained invested and the jobs were created.
Your spouse or child working in the enterprise cannot be used as one of your qualifying EB-5 workers.