I would recommend talking with your local university(s) to find specific answers as to the recommended course of study. A career counselor at the university will also be a resource to help you in planning and setting goals.You will definitely need a masters and a masters in education/administration, the program can vary from university to university but should be accredited with state standards. In many school systems, a PhD is preferred. In my state, there is also additional credentialing needed in addition to the degrees and classroom experience.

I will tell you this, there is fierce competition for principal positions and most principals start out by being an assistant principal. In either case, it will require many years of classroom instruction, so that should be your first start or clue whether you want to proceed on this career path. Principals are not considered without time in the classroom. If you are considering teaching, English Lit will be a tough subject to find a position in but not impossible. There are many more English graduates than positions. And you must be certified and licensed to teach, your department of education will have information on the requirements in Michigan. Licensing will also require continuing education to renew, usually is on a 5 year cycle.

It is a tough job in many cases and I would think Detroit's schools would be full of challenges. You may also be able to get additional information from your state's principal association. You can google it, should be under Michigan School Principal Association or something similar or check with the state department of education. Your state department of education will also have information (should be on the website) as to credentials/licensing requirements for principals as well as teaching.

Good luck!