Can I sell my e-book in Amazon Kindle Direct?

Hey guys, I'm underaged. I'm 15. I recently wrote a book here in Portugal in english. However, it's very hard and costly to sell an english book here in Portugal. So I decided to sell in the US. I found Amazon Kindle Direct. I created an account. I tought that my income from selling the book would go to a paypal account, but I came upon a tax information interview. Here in Portugal minors cannot create bank accounts. And I dont know if minors can fill IRS documents. I don't want to get in trouble or get arrested, so, do I need to have an agent who is an adult, to act on my behalf? Do my agent needs to use my TIN number or does he uses his own? And then can I use the money I earn?
Note: I'm not an US citizen.
Added (1). Edit: Do I have to have ISBN in my name?
Added (2). Again, can I register the copyright in the US Copyright Office or does my agent needs to register it for me?

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