Not all Usernames get automatically approved by the Username System when a new Penguin is created, such as your Username in-game looking like this (P123456). To fix this, you can do multiple things to get it approved or not if it’s not an appropriate username.
Most easiest way is to ask a Moderator in-game to approve it. Moderators have a M Badge as a Pin. Another way is to contact the CPR Support Team (email@example.com). Or you can tweet @CPRSupport and/or @CPRewritten.