I think that is in your interest to show the result of str(covid_age) . It is polite to give readers that invest some time in your problem the information you and they think is relevant.
The standard procedure is to provide a reprex .
Looking for a solution I saw on the repository of the ggpol package that the function facet_share is currently not supported: issue7
For another way to create a pyramid see https://forum.posit.co/t/adding-legend-to-ggplot/73644