hi everyone. I finally decided to go back to school this year and get an A.S. degree in Physical Therapy Assistant at a community college. but first i have to take these 3 prerequisites; human anatomy & physiology (4 semester units, including a lab) Math - intermediate algebra or higher (3 units) and English composition or equivalent (3 semester units) before i can do that. this will be my first time going to college and i have no idea where to start or what to do. when is the best time to register? what is the difference between units and semester units? how long will it take me to finish these classes? can it be done within a year? the reason why I’m asking is because i need to have these prerequisites ready before March 2016, which will be the deadline for PTA Program Fall 2016 application. i already applied for financial aid and was eligible for pell grant and loan. now i was wondering if i could use financial aid to pay for those courses? thank you in advance! 
A few issues that may affect your plan: 1. You will probably need to take a placement test for the math, and it is possible you could place in a level lower than intermediate algebra. If so, that will require you to take additional math courses. 2. There may also be an English placement test required, which could also affect your ability to take college English comp. 3. There are often prerequisites for anatomy and physiology. Usually high school bio and high school chem (or the college level equivalents) are required before you can take anatomy and physiology. Also, anatomy and physiology are often high demand courses at community college and fill up quickly. Depending on your college, you may have to wait until you have enough credits to be able to register in the priority group that will allow you to get in the course.
It sounds like the courses you listed could each be completed in one semester, assuming you meet the prerequisites for these courses. Your best bet is to meet with an advisor at your community college and they can give you specific information for that college.