Naturalization. A person could file the application for naturalization 90 days before you complete your permanent residence requirement if your eligibility for naturalization is based upon being a: Permanent resident for at least 5 years; or Permanent resident for at least 3 years if you are married to a US citizen.
It is important to consult an experienced attorney before applying for naturalization because depending of you background, you might lose your permanent resident card and put yourself into removal proceedings.
Citizenship. Some individuals might have automatically acquired or derived citizenship at birth or after birth. In order to be able to determine if you have acquired automatic citizenship through your parents or grandparents, you should consult an experienced immigration attorney. The immigration laws in this area have been very changeable and depending on your birth date, might depend whether you acquired derivative citizenship.