Startup Idea: App Development for Tutoring Business Management

Startup idea to build a mobile app for a tutoring business. The app should handle invoicing, contracts, employee hours tracking and student progress tracking conveniently on a mobile device. It should be user-friendly for the business owner, employees, and clients.

I run a small tutoring company that has grown from a few core students to several employees and over 75 students.
I am, unfortunately, still using my basic contracts and doing invoicing and payrolls manually, as well as student progress tracking etc. What would be ideal for me is an app that I, my employees, and my clients could download, in which I could invoice, contract, and show student tracking all in one place. My employees could track their hours with their students, and provide feedback as well.
I don't have a lot of time to sit down in front of a regular computer during a business day, because I see clients constantly. It would be much easier to pick my phone up and handle the reporting this way. I tried creating it through Access (a desktop solution). I utterly failed.