There is adequate preparation required in any stream of study or work you choose.
Here is what a highschool student should do if they intend to join medicine at later stage -
High school students who think they want to attend medical school will do well to prepare themselves academically by taking the most rigorous courses offered at their high schools (a mixture of Honors, AP and/or IB courses), get the highest grades they can and score well on the SAT and/or ACT, proof to admissions officers that they have the wherewithal to thrive in their schools. Colleges also look for students who demonstrate a true love of learning.
Where high schoolers choose to attend college is also an important issue. Incorrectly, many people think that the more prestigious an undergraduate college is, the better the chances are for a student to get into med school. Not true. Acceptance into medical programs often has more to do with how students maximize the resources and opportunities provided at whatever college they happen to attend. As it happens, small, liberal arts colleges often offer the best preparation for medical school because students have greater access to accessible professors who actually teach and mentor them. Undergraduate research opportunities also tend to be more available at small colleges. Have a look at the National Science Foundation list of the “Top Schools from which S&E (Science and Engineering) Doctorate Recipients Received Bachelor’s Degrees.” Lots of small, liberal arts colleges are on that list, many of which you may not have even heard of.
Another piece of misinformation is that students must be Pre-Med majors, or at least science majors, to get into medical school. Wrong again. According to NACAC experts, a very good student has a better chance of getting into the most selective medical schools by majoring in something other than Biology (or another science). Med schools now look for students who have broad, liberal educations that will help them relate to the world beyond their science interests. As a result, future medical students can major in anything they want, including art history, Russian, or horticulture, so long as they take the required pre-medical school classes (see list below) and score well on the Medical School Admissions Test (MCAT).
The usual required courses for acceptance into medical school are:
1 year, freshman Chemistry with associated lab
1 year, Organic Chemistry with associated lab
1 year of Biology with associated lab
1 year of Physics with associated lab
1 year of English
1 year of Calculus or other advanced Math, including Statistics
You might find more details at - http://www.huffingtonpost.com/marjorie-hansen-shaevitz/so-you-want-to-go-to-medi_b_5347725.html
Hope this information helps in getting fair idea of what would be the next set of steps.
Wish you the best! Do well.