CNA

Im planning on taking a course at Lee college. But everyone there keeps giving me the run around.. and Im wondering if i can just study for the cna exam, and volenteer at a clinic to get the experience? And get my liscense after that?
But if i do take the course at the college, is there a certin age You have to be to take the exam?
Because im 17, and they told me i can take the course.. but im wondering if in the end, and after i pay almost $700 if i can even take the exam?