Being a CNA is a great job, and most certified nursing assistant programs take between four and 12 weeks. This is broken into instructional hours and clinical practice. A typical 120-hour CNA program offered over six weeks may include four weeks in class and two weeks in a clinical setting, depending on state guidelines.
It looks like you might be interested in applying to nursing schools in the future. I worked as a CNA before starting PA school, so I may be able to help you with some questions. Let me know if you have any specific questions.