Why not? If you can dream it up, you can make a game out of it, provided you are dedicated and creative enough to do it. Depending on your experience with the tools and level design, it might be very difficult, it's a big job to learn the tools and to motivate a team who believes in your project enough to commit their time and resources to help. So you've got to be pretty serious and certainly put in hundreds of hours. Though you could start tinkering around with the idea now, in an app like blender or wings, and start putting something together in 3dgs, and have fun, you might at least learn a lot, if not have something with which you could excite enough people to help you make it.