Hi,
Could you please clarify the question? Not sure if you are asking if you could join a US College in the 2nd half of the academic year which typically runs from Aug/Sep to May/June of the next year. Colleges that allow Spring Admission (startin...

Yes, students at US Colleges have a broad flexibility in picking courses and deciding what degrees they want to pursue.
The main course of study for a degree is called a "Major" and one can pursue dual or more majors. For each major you need to ac...