Pick a major that interests you so you don't mind devoting a majority of your hours to studying. You will need to get good grades in college in order to apply for medical school. At the medical school I attended, the average GPA is reported to be 3.85, so even one or two B's can hurt your chances of acceptance.
Aside from this, any major is acceptable as long as you complete the prerequisite courses.
During college study for and complete the MCAT. Devote an entire summer to studying for the MCAT and consider paying for a prep course if you can afford it.
Medical school takes 4 years to complete.
After medical school physicians complete a residency for additional training. These can last 3-6 years and are sometimes followed by an additional year or two of fellowship subspecialty training.
In terms of education, the minimum requirements are an undergraduate degree, 4 years of medical school, and then a few years of surgical residency.
If helping others and becoming a surgeon is your dream, the many years of school will be worthwhile in the end!