Yep, we just had our first exam (electricity).
Are you planning on the summer + one year plan or a two year plan?
If you're dead set on the one year plan (which I would strongly recommend you not do) you have to take general chemistry during the summer, since it's a prerequisite for organic chemistry. You follow that up with Orgo, Bio and Physics during the year, and kiss your social life goodbye, because those classes will eat you up.
If you're going to do the two year plan, I would totally recommend biology first, especially coming from a non-science background. General biology will set the groundwork for many classes to come. Fixsen's class, while difficult, is supposedly an ideal introductory biology course, and it will prepare you beautifully for the MCAT. Taking Biology in the summer also opens your schedule up for a variety of upper level science electives. Cell biology, microbiology, molecular biology, genetics, etc. all require introductory biology.
If I were you I would set up my schedule as follows. Keep in mind this varies based on your EC activities and how much torture you want to put yourself through.
1. Summer Biology w/ Fixsen - start looking around for volunteer/EC activities, but make your priority earning that A
2. Chem and Physics with Tucci and Ruckner, respectively, this coming fall. Do not take a third course until you get the feel for their classes. Both can be time sinks if you suck at time management. Secure a good volunteer gig, and stay busy during the day.
3. Chem and Physics II, and Cell Biology next spring. This is my current schedule, and I find it both manageable and interesting. Cell bio really helps to hammer home concepts learned in introductory biology.
4. The following summer (if funds permit) molecular biology and biochemistry. Show those adcoms you can handle some tough upper level science coursework. Summer biochemistry does not require organic chemistry, and may even help you with the course when you take it during the year.
5. Organic Chemistry I and II and Anatomy and Physiology I and II the following fall and spring. Aim for a late April MCAT (since it only covers the first semester of O-Chem). Start studying after your fall finals. With your MCAT done at the end of April you have a least a week, week and a half, before finals. Scores come back at the end of May, and you're right on target for a nice and early application.
Hope this helps,