How do people become professional programmers? Many people go the “traditional” path through a computer science or software engineering education and from there into professional programming work. Others become professional programmers by accident. A person writes a small program to help at work, and their workmates say, “Oh great, you can write programs! You’re our programmer now!”

This article explains what’s a real professional software developer, the real meaning of “Professional”

http://www.developerdotstar.com/mag/articles/software_professionalism.html