For general career info: http://www.bls.gov/oco/ocos166.htm#nature
and then can scroll down to the different sections of the entry.
My cousin had gone to school for OTA, and the job may be both mentally and physically draining albeit rewarding. Most jobs in the field are in a nursing home/long-term care facility. Please also be aware that the ot aide is very different from the ot assistant and the ot aide does NOT need formal training unlike the ot assistant. For ot assistant, the student must successfully complete a full-time clinical fieldwork experience component.
Before taking prerequisite courses, please job shadow/observe in the various departments that OT may be provides including a physical rehabilitation hospital for those with Traumatic Brain Injury (TBI), spinal cord injury/paralysis, stroke ("brain attack") which is a type of brain injury, shoulder/knee/hip replacement, amputated limb, hip replacement or such - pediatric hospital - nursing home setting.
With regard to prereq classes in the sciences and other courses, please check with the program(s) in which you're interested Before taking certain ones since not all may transfer. For example, 'human anatomy' usually does NOT transfer but instead perhaps 'general anatomy and physiology' so it's best to check with those programs beforehand.
Pertaining to schooling, consider the more affordable Community College and forgo those private overpriced For-profit tech schools such as pima institute, anthem, keiser, brown mackie, everest, sanford brown and others as they are merely out to "make a profit" (** and course credits may NOT transfer to other schools **).
These consumer sites have negative posts by former students of those private $$ for-profit tech schools, and please heed the students' warnings:
and can type into search.
For accredited programs in ota: http://www.aota.org/Students/Schools.aspx
U.S. colleges: http://www.utexas.edu/world/univ
For possible volunteer opportunities (though most likely non-direct patient care): http://www.volunteermatch.org