Partitions used to be useful when hard drive space was really expensive.
1 partition for the OS, 1 partition for music, 1 partition for games.
Today, not so much. This is much better done with individual drives and, secondarily, individual folders.
1 drive for the OS and applications, other drives for other things. Other things split into top level folders.
Standard axiom of partitioning - whatever partition you want to work with will be just barely too small.
(And next time you want assistance with homework, don't be so transparent... )
If you make a "programs" partition and a "documents" partition, and put Windows/apps/games on the first, and your user data on the other, if you managed to break Windows (e.g. by accidentally deleting a system file), you can do a format and reinstall without blatting your documents.
Drawbacks have already been covered (plus, if you goof on the partition sizing, it can be a pain to fix).