Prior to 1820, information on the age and sex of slaves was not collected, simply the number of slaves was taken down for each household.
It isn’t clear what happened to the first volume of the 1810 Census returns titled “1810 Census: Aggregate Amount of Each Description of Persons within the United States of America, and the Territories” (it is also missing from the Census Bureau’s digital collection). Unfortunately, it was probably lost at some point very long ago.