Age Adjusted Incidence Rates Using Poisson Regression

#1
Hello,

I am not sure how to calculate age-adjusted incidence rates using poisson regression. I am comparing injuries for children at two schools, offset by child-days in school and would like to adjust for age. I ran the following model:
poisson injuries school i.age, offset(childdays)

I am able to determine age specific incidence rates and an age adjusted incidence rate ratio but don't know how to calculate an age adjusted incidence rate for the two schools.

Thanks!
Hannah