Can you take 5 classes (15 credits) and still have a healthy social life like going Greek?
The answer is entirely dependent on how difficult/time consuming the work for those classes are, and how intensive the rushing process is at your university, as well as your personal ability to handle having a lot on your plate. Lower-stress classes and a fairly relaxed rush? You’ll probably fine. Intense, upper-division classes, perhaps with a lab, and a more stressful rushing process? Probably not. Do some research about the rushing process at your university, ask around about classes and professors. Then you’ll be able to make an informed decision.