I think one very important key factor one should have to become a real developer is concept and originality of code. I think this separates real web developer from the rest. Someone who develops using whatever technique implementation he wants from his own concept and how he wants to relay that concept.
Originality of the code is also important, though Im not saying using CMS is bad but anyone can develop a site using any CMS, but if you really want to become a developer, try to develop a site using your own code from scratch. Technical Skills can be learned, but conceptualizing is a different thing, starting from scratch and building your own logic and program design.
If you have tried building a site using your own concept and your own code then you can consider yourself a web developer.