If I am here in the US and I am an immigrant, my fiancé is a citizen, we want to get married in the court house, does that mean she is sponsoring me?

Becoming married to a U.S. citizen, whether in a courthouse or otherwise, does not, by itself, constitute a sponsorship for immigration benefits nor does it produce immigration benefits. Nonetheless, marriage to a U.S. citizen can form the basis upon which the U.S. citizen may sponsor a foreign national spouse in an "adjustment of status" application process by which the foreign national spouse would apply to become a Lawful Permanent Resident (sometimes called getting a "Green Card"). There are many other details that govern eligibility to adjust status. There really is no substitute for you and your fiance to consult with an immigration attorney who, after learning all of the relevant information, could advise about eligibilities, options, and strategies to attain your goals, and who then could offer legal representation in the often complex application process. Some immigration law firms, including mine, offer legal services on a "flat fee" basis so that a client will know the total expense from the very beginning, and a few immigration law firms, including mine, offer an initial consultation free of charge.