Can we both still get married and file our paper work if I almost overstayed?

Although not entirely clear from your question, it sounds like your girlfriend is a U.S. citizen; you entered the U.S. lawfully and with inspection; your non immigrant visa soon will expire; you and your girlfriend plan to become married; and you are interested in applying to adjust status to become a U.S. Lawful Permanent Resident (to get a "Green Card"). Generally, if a foreign national entered the U.S. lawfully and with inspection, such as with a B2 visitor's visa, and then becomes married to a U.S. citizen, the fact that he may have overstayed his visa (or even worked without authorization) will not stand in the way of eligibility to adjust status in the U.S., and there will be no requirement that he go outside the U.S. for immigration steps. Especially since you and your fiancee are less than fully familiar with U.S. immigration laws, and failure to properly prepare and fully document an application can cause substantial delay or even more harsh consequences, it would be wise for you and your fiancee to consult with an immigration attorney who, after learning all of the relevant facts about you, your immigration history and related issues, will be able to advise about eligibilities, options and strategies, and offer legal representation in the often complex application process.