Primary Cardholders of TD Credit Cards must be at least 18 years of age. However, it is possible for the Primary Cardholder to add an Authorized User to their TD Credit Card Account who is under the age of 18. The Primary Cardholder remains responsible for all purchases, balances and fees made to the Account. Students who are 18 years of age and older and who have no credit history can apply for a TD Canada Trust Credit Card for students.