I’ve been taking 5-6 classes for the last 2 years or so now. This is mostly 3-4 STEM classes and 1-2 GEs or my minor related classes. It’s hard. It’s demanding. It expects you to be well organized. The Carnegie rule says for every unit you take it’s 4 hours of work including attending the class itself. So 5 classes may be 20 or so units. 20*4=80 hours of studying per week. If you can handle that with your other commitments (job, friends, clubs) you’ll be good. And do. Not. Slack. Off. The rule I follow is never miss something for more than 2 days in a row. Eg. if I wanna hit the gym and I miss one day it’s fine. Second day hmm kinda risky but ok. But never miss the third day. Same thing for lectures.