your question doesn't provide enough information for us to understand the facts of your situation sufficiently to answer but generally you should call the social security administration and ask them. You're entitled to collect your own social security income whether you are married or not. If you are collecting a prior spouse's ssi or parent's ssi then yes, getting married now would end that.
Disclaimer: Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.
If your spouse is not eligible for SSI, your SSI could be reduced; your spouse's income and resources will be considered or "deemed" in determining your financial eligibility. If your spouse is also receiving SSI, you and your spouse will receive the amount for a couple, which is lower than you and your spouse each receiving a separate grant.
Your local SSA office can probably answer your questions with greater specificity.