Read the general life across the border overview
A child's twenty-first birthday falling inside a planned assignment is a scheduling fact with legal consequences, and the parent's extension does not resolve it. Dependent categories carry age and marital-status conditions, and immigrant categories calculate age under their own rules. Ask for an individualized review of that specific child, on the actual dates, before anyone commits to a multi-year plan.
Write the dates down before assuming anything
Record the child's date of birth, the intended start of the assignment, the validity you expect to request, and the school year you hope to complete. Then identify the status the child would actually hold. TD status, for example, is available to unmarried children under 21, permits study and does not authorize employment; other dependent categories carry their own conditions, and employment rules that apply to a qualifying spouse do not extend to children. Put the birthday on the same timeline as the requested validity dates so the collision is visible to everyone reading the file.
Separate nonimmigrant status from immigrant age calculations
Do not assume that an approval for the parent extends the child's dependent status past an age condition, and do not assume an age is frozen because something has been filed. Where an immigrant category is in play, the Child Status Protection Act may affect how age is calculated, but that is an individualized calculation depending on the category, the filing and visa availability. Hypothetical example: a family plans a three-year posting and the child turns 21 in month twenty. The question to put to the reviewer is what the child's status would be the day after that birthday, and what alternatives would have to be prepared in advance.
List the decisions that depend on the answer
Housing, school enrolment, a spouse's employment plans and the child's own postsecondary intentions all sit downstream of that answer. Mark which of them are reversible and which carry penalties or deposits. If the child hopes to take on unpaid activity such as an internship or volunteering, flag it for specific review rather than assuming that unpaid means permitted. Agree with the person handling the file on who to contact if the departure date moves, because shifting dates can move the birthday relative to the requested validity period and change which questions are urgent.
Check which household commitments carry a penalty
Family plans are held together by contracts, and those contracts carry dates of their own. A school enrolment agreement may require a term's notice or forfeit a deposit; a residential lease may run past the assignment and carry an early-termination charge; a relocation policy may make an advance repayable where the posting is cut short. Note the notice period and the exit cost for each, then set them beside the birthday and the requested validity dates. Where a commitment is expensive to unwind and a status question is unresolved, resolve the question first. Ask before the deposit clears.
What else is on your mind?
Is a matching job title enough for TN?Can years of experience replace a degree for TN?Can my own U.S. company employ me under TN?Can my spouse work if I hold TN status?Editorial source review: 2026-09-07. General preparation guidance, not an individual assessment.