Yes well said, one can know the child but then the child grows into an adult, so who is the real person? There is a text in the Vedic literature known as Bhagavad Gita that translates from the Sanskrit to says,

"As the embodied soul passes in this body from boyhood to youth to old age, the soul similarly passes into another body at death. A sober person is not bewildered by such a change."

Sat chid ananda is apparently our original nature,eternal, fully conscious and blissful.