Several months ago you would have been prompted to change your Facebook username – the name that appears at the end of your profile URL.
If you don’t like it, you can change it. Head to the Settings page on Facebook by pressing on the arrow in the top-right corner, and then on Account Settings.
On the front page, you’ll see the option to edit your username. Press edit, change your username, and then press “save changes”.
However, keep in mind you can only change it once. Make it count!