Change individual account to developer

hi everyone 

I am tring to change my individual account to developer account, I belive that i tried everything without sucess.

Follow a step by step of my atenpts.

When I go to developer console appers a msg tell me to sign up with developer accout, and I click on "Lear More", I try to follow everything that says in the article

When I go on Developer portal, I have two options "Get Started" or

"Go to dev console"

if I click on "Get Started" is just a tutorial and if I click on "Go to dev console", I just redirect to a page that ask me if I am a part of box corporate, i click "no" and go to normal login page

If I go to Developer Sign Up Page, ask me to create a new user

If i try put my email, says that already taken