Wrong age Category in Today's Plan 2021

I changed age groups this year, or at least I think I should have. However Today’s plan has me in a younger age group than I think I should be in. Is there a formula for calculating age that sets the age for the year on January first, so that I would really be in the younger age group, or is my age miscalculated in Today’s Plan?

Thank you.

I think you can change your date of birth on Today’s Plan, and choose to reprocess the workout file. Not sure it will solve the problem, but I guess you can ask Today’s Plan if it doesn’t work?