According to the psychological theory of ontogenetic development of the psyche, the child's consciousness can be ascertained only after the stage at which the child begins to use all sorts of pronouns in his speech, respectively, separating himself from others. Also, at an earlier stage, the child's consciousness can be revealed by his ability to recognize himself. For example, an experiment was conducted where children of different ages were deliberately soiled their nose or part of their face in front of a mirror. Younger children (1-1.5 years old) did nothing in such situations, while older children (2-3 years old), on the contrary, noticed a change in their appearance and interacted with the soiled area of the face.
Fundamental works in the development of the psyche in ontogenesis belong to Jean Piaget and Lev Vygotsky.
I was about three years old, and for the first time I remembered something. Before that, I could only think about what was happening right now. I believe that this is how my awareness began.