Disagree. While it helps, and many programmers are also general designers, the people in this category can come from any background, though in many settings the most direct path to this is through the design department (level design, mainly, but again the role of the designer varies greatly from company to company). In some companies, design is split between designers and environment artists, in others it's more dual-role (I personally fall into the latter).

The best advice I can give: Start something, stick to it, finish it. If you can do it well in your spare time, you'll do it well full-time.

Also, don't spread yourself too thin. It's enticing to try and learn a level editor, modeling software, photoshop, c++, etc., but it's generally going to be better to develop strong skills in one before venturing to any others. I came here with little to no modeling experience and some ever-so-slight C++ from high school (self-taught) and Java from college (3 years ago), and have expanded into some small modeling and slightly less small scripting roles within the 9 months I've been here.

And finally, never be frightened or intimidated by next-gen tech and don't force yourself ahead just for the sake of doing so. Polycounts are getting higher, resolution is getting higher, but enjoyable and well-thought out design is the same as it ever was. Two of us here (myself and Ken Banks) got here on HL engine work alone and jumped straight to Doom3 in no time - I was up and running on production work within a week. If/when you're immersed in a setting full of talented people, you will learn what you need to know far quicker than you could ever hope to on your own (see above example of modeling/scripting).

Is that coke can render from a tutorial or something? I swear I've seen it dozens of times now Car looks pretty awesome though, nice work