How do I get a pro (basic) subscription for my child

I’m trying to get the free pro account for my daughter, who is a minor. She has a basic profile on imdb (not pro) and I created an amazon account in her name but to continue, I am prompted to add a credit card number with the name that matches the account. My child is a minor and therefore doesn’t have a credit card. How do I create a pro account for her? I have my own pro account.