If you are implying that consciousness pertaining to awareness originates in the brain, then I am inclined to agree with you. If you are implying that consciousness pertaining to the self/identity originates in the brain, then that is not a fact. That is an opinion held by materialists/physicalists that has yet to be proven to be true and has yet to have any sufficient evidence supporting it. Correlation between the mind and brain does not mean causation.
"It was an All-in-One and One-in-All of limitless being and self—not merely a thing of one Space-Time continuum, but allied to the ultimate animating essence of existence's whole unbounded sweep—the last, utter sweep which has no confines and which outreaches fancy and mathematics alike."
Age has nothing to do with it. If the nameless mist was the all in one, Lovecraft or another author would have said so.