If you have access to the class syllabus or even just a brief overview of the topics covered, that will likely give you better idea of whether or not you’re prepared as the rigor of the class will vary depending upon a variety of factors. Also, talk to others in your school to try to gauge the rigor and structure of the course.
What is the “drop” policy at your school? If you’re able to switch into a regular or “college-prep” calculus class, or even a similar course, try AP Calc out first and then switch later if you’re in over your head.
Assuming you’re a high school student, you might want to post in the High School Life thread, as you’ll probably yield more detailed responses: http://talk.collegeconfidential.com/high-school-life/