I would hit at least 50 hours of shadowing (per adcom's recommendation on SDN) and increase your non-clinical volunteering hours. Perhaps your tutoring of underserved children can count, but I would increase. Many applicants have around 200 hours. And yups, to have a good chance of MD, aim for 510-512. If your MCAT score in April is lower, I would add DO schools. Come back with your MCAT score next year, and I'm sure you'll get a plethora of advice. Good luck, you got this!