Deprecated doesn't mean gone, and the old functionality is not actually going away. But if you want to keep abreast of the state of the art, write for GLES 2.0 and up, or port your knowledge to DX10 and up, then yes, you'll have to ditch that fixed function pipeline.
The intermediate step you could take that's still old deprecated functionality but still gets you moving in the right direction would be to learn how to use Vertex Arrays. Still, it's probably easier overall to just unlearn what you know and start with all new tutorials for the programmable pipeline. A couple resources:
- meant to accompany the tutorial at http://www.arcsynthesis.org/gltut/