you are eligible if you are not covered by any non-HDHp such as Medicare. However, you may have additional insurance that only covers the following items.
- accident
- disability
- dental care
- vision care
- long-term care
- telehealth and other remote care (for plan years beginning before 2022)
- liabilities related to workmen's compensation laws, tort or ownership or use of property
- specific diseases or illnesses
- a fixed amount per period of hospitalization
you can make a full year's contribution if HSA-eligible on December 1st
I'm assuming you're single and can not be claimed as a dependent by someone else
