You have got it all backwards.
1st. Taking the MCAT and possibly doing well in it is not the way to gauge whether medical school is right for you. Doing ECs like clinical volunteering and nonclinical volunteering with service to those less privileged than you, etc is how you gauge whether you can spend the rest of your life as a physician in service to ill patients. Your ECs will give you a clear indication of whether you should begin your journey to medical school.
2nd. As a nonscience major with a nonscience master, you will be doing yourself a huge disservice by attempting to self-study for the MCAT before taking the science prereqs, especially biochemistry. Taking your science prereqs at a CC is fine since you are a nontrad.
Finally, if you are not passionate about medicine and your heart is not in it, then please don't waste the time, energy, and money taking this journey.