As @Jugulator20 said it, medicine (MD and becoming a doctor) in this country is…“a marathon, not a sprint”. Not discouraging you, but I have seen too many take that path, only to drop off at some future point. Not just pre-med science courses are difficult, but MCAT and MD are too. Redesigned MCAT is 7 hours and 30 minutes long. It doesn’t end with MCAT…more tests in the future…USMLE I/II/III, board exam. It is a noble profession, but not for everyone. It is doable, but requires a long commitment.