If you aren't ready to start a full program, non-degree/visiting student status is what you're looking for. At NJIT, you can take up to three graduate or five undergraduate courses without officially applying for entrance to a program of study.
CriteriaUndergraduate: Must possess an appropriate academic background or have successfully completed prerequisite coursework.
Graduate: Must possess a four-year bachelor's degree (or its equivalent) from an accredited university.
Application Checklist
Keep in mind that if you later decide to pursue a graduate degree, you'll still need to go through the full admission process.
Registration Instructions