I have been approached by dSLR Photography magazine (http://www.digitalslrphoto.com) to publish my photo “Flamingo Abstract” as part of an article on bird photography. They purchased the rights for a one time use and the article will be published 3/12/2013. This came as a bolt from the blue. They saw my photo on the website 500px.com, a photo sharing site. Since this is my first sale can I start calling myself a professional photographer?