Another option, if you are motivated, is to go through http://cs10.org on your own if you are unable to take AP CS principles. This is the kind of college course that was a model for AP CS principles.
In terms of the two AP CS courses:
- AP CS principles gives a broader overview of CS, and is suitable for non-CS majors as well as prospective or possible CS majors.
- AP CS A may give advanced placement for CS majors at some colleges where programming and data structures are taught using Java or a similar language.