Well of course you can!
Here is one thing: You can change your username that is visible to everyone on the forum, like 'Kennedy', the one you have. But, you cannot change your username that will be visible to everyone when you play the game. If you want to change your username Kennedy to be visible on the forum, go to 'Profile' (Located under Hello -yourusername-) then 'Account related settings'. Under username, type the name you want to change in the box next to Name.
In order for this to work, you will need to change your Email and password.
You can make a spare account on Yahoo or Hotmail or any website that you use. It's useful if anything happens.