I found my old dream journal from 2009, back when I first got into lucid dreaming. And it turns out that there's an extra lucid dream that I had forgotten all about. D'oh! So I've had four total lucids and not three.
It's too bad that I can't remember it, because my journal entry makes it sound pretty interesting. I was in a playground, and I had asked a dream character what the difference between the dream world and the waking world was. She replied that people in the waking world are limited by their own knowledge and experiences, but in the dream world, we're all connected to a sort of mass consciousness. She called this the "language" of the dream world. So I focused on this idea of a so-called dream language, and immediately the playground scene around me dimmed to expose an entirely different landscape hiding just beneath the surface. I stopped focusing, and everything snapped back to the way it was. The dream character smiled approvingly at me and said, "See what I mean? It's all about the language!" I ended up using this technique again later on, when I wanted the dream scene to change to something random, and it worked then too. But then again, the changes still came from my own memories, so I'm not really sure what a mass consciousness had to do with it. Lol. Silly dream character.