You are up to date if you have received the dose(s) that CDC recommends for your age group. Vaccine recommendations are different depending on your age, you medical conditions, the number of doses you have received and the time since last dose, as shown here. Learn more about COVID-19 vaccine recommendations specifically for people who are moderately or severely immunocompromised.
The CDC has guidance for everyone 6 months and older based on age and medical condition.