What can I do if I'm a 22 year old US citizen who wants to fix my mother's papers?

There is no law or regulation that requires an applicant to be represented by an attorney in an immigration-related application process, and in fact some people successfully navigate the application process without legal representation, especially in the very most simple cases. The situation you described certainly is not a simple case, and even determining whether your mother may be eligible to apply for adjustment of status would require additional information, such as details about her initial entry into the U.S. Failure to properly prepare and fully document an application, or filing an application for someone who does not qualify, can result in delays, denials and even more harsh consequences. It would be wise to engage an immigration attorney to provide legal representation to you and your mother regarding an application in the Immediate Relative visa category. 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.