This can absolutely be done. You just need to make sure you put in the time and effort. I took my first diagnostic and received a 498. For 5 months I put in at least 40 hours per week studying on top of my job and 2 hour each way commute to work. I ended up getting a 514 on the MCAT. A guy I know took the old MCAT and got like a 27 and studied like crazy and took a lot of practice exams and ended up with a 36. Give yourself time. Don't rush it. Take it when you are ready and truly feel prepared. You got this!