I can create a hotel reservation system in the amount of time it takes me to walk to the supply room and grab a calendar and a pen. I could also work full time

I can create a hotel reservation system in the amount of time it takes me to walk to the supply room and grab a calendar and a pen. I could also work full time for the rest of my life on one. It all depends on the requirements. No one is going to be able to tell you how long it will take for your particular system. That said, the person you should be talking to is whoever is supervising your internship. Let them know what your school requires and ask them what you can do to meet that requirement. Then talk to your school and ask if what the company proposed meets your credit requirement. Then continue going back and forth until you find a mutually satisfactory arrangement. Maybe the model of the system could count as a finished project for your school. The only people who know are the people you have access to and we do not, so we can't answer this question for you.