Facebook has changed the rules relating to Facebook page usernames.
Previously, to have a user-specified username for your page, you needed 25 likes. This would then give you the option to give your page a tidy URL i.e. www.facebook.com/samflynnsocialmedia rather than the long URLs with numbers and letters mixed up that would make it impossible to add to marketing literature.
So, no matter how many likes you have on Facebook, you can and should claim your username and start promoting your Facebook page on your marketing material.
To get the username for your page, go to www.facebook.com/username.