* Un estudiante de Northwest Community College: This is the most literal and common translation. It means "a student of Northwest Community College."
* Un alumno de Northwest Community College: This is also very common and uses "alumno," which is another word for student.
* Un estudiante del Northwest Community College: This uses "del" instead of "de," indicating possession more directly. It's grammatically correct, but the difference is subtle.
All three options are perfectly acceptable and understandable. Choose whichever sounds best in the context of your sentence.