A visa is a grant of permission to enter the country. No inoculations are required to enter the US, unless you were recently in a country with epidemics such as cholera and yellow fever. You must be law-abiding.
Criminal behavior is grounds for deportation.
You must be able to support yourself financially during your stay. You intend to leave the US after you complete your studies. F-1 students may stay in the US for the full length of their academic program plus 60 days. The J-1 visa is issued for students needing practical training that is not available in their home country to complete their academic program. The training must be directly related to the academic program.