Our first awareness after we are born is that of the self. With whatever tools of cognition we then have we cognize that we are the body. We look around ourselves and notice that all persons around us have bodies as well. Everybody's body is finite and unconnected with the others. We realize we are all finite, separate and unconnected individuals. Not only us as people, but everything else too looks finite with defined boundaries, unconnected.
Is this complete self awareness? Of course, it is not. As we grow, we soon learn that we are much more than the body. But body is the only self awareness with which we begin the hourney of life. If body is all we know we are, its survival is our paramount purpose.