Don't we all "shape shift" when we dream, though, or go OBE? I shape shift into a different version of myself, wearing a different outfit sometimes when I go OBE or from LD to OBE. I had a very lucid dream where I was wearing jeans and a t shirt and then I astrally projected into a version of myself that was wearing some floaty ethereal outfit and had really long, wavy hair, that was down to my ankles. So you could say I shape shifted into the version of myself that I wanted to experience in that moment. Life is a lot like that, as well. We all shift into this 3D reality upon birth and this is the form we took. Is this really us? No, it's what we have chosen to appear as. I imagine the same applies to the astral, considering the astral works through thought manifestation... I guess what I'm trying to say is, just imagine yourself being a different form (human or animal) and hope you have the Yoda mind skills to pull it off? If you don't pull it off, honestly you don't have the energy to shape shift just yet. Simple as that. My two cents. Just going off my own experience, my common knowledge, and my opinion. It's really hard to be right or wrong about things like this because everything is subjective.