About getting the school/college chop, cant it wait till the weekends? I am sure most colleges are open during weekends right? Is your college strict about this issue? Meaning as soon as you clock in on the 1st day of internship u have to report back to them?

About the black colour it is a controversial/non-confirming colour. Why create such an impression on the 1st day? To some wearing all black is cool, but if the boss is sensitive he might be thinking that you are treating his company like a funeral. Anyway bottom line, why create controversy on your first job?