I've managed to continue my undergrad education while co-founding an angel back startup. Although I didn't intentionally plan it, doing both at the same time as really helped me learn. What you learn in school can instantly be translated back to your startup, instead of waiting several years after school when you have forgotten much of it. It goes the other way too, lessons I've learned in my startup help me focus on what matters in school and "project manage" my course-load and homework.
It's not for everyone, and I am not saying that you have to start a company while in school. But at the very least, consider joining a startup while in school. Most startups are very flexible to where you work and what hours you work. It's usually a great fit while in school.