You can call yourself whatever you want.

Nobody says you can't have a different name every day, if that's your wish. Reinvent your life, create a new past, change your birth year, and tell new stories, nobody cares if you do. Become whoever you want to be but just know that, as in the book "Calamity: The Many Lives of Calamity Jane" by Karen R. Jones, the truth might catch up.