Under grad students have the biggest advantage of having flexible courses which allow them to study subjects of their choice across various streams. So you may take business or engineering courses , yet follow your interests in science, Literature, music, theater, film making and the arts. US Universities gives you options to make your permutations , studying a diverse combinations of subjects.
For Post grad courses, most US universities require a 16 year education. There are some universities like University of Massachusetts that accept a 15 year education. USA offers Post grad options in a large number of specializations like Art, Engineering, Culinary Arts, Fashion, Business, Finance and many more.