I dont understand how I can make sure my teacher keeps track of my progress?
If you go to your settings there is an option for Progress Sharing. If you put your teacher's DuoLingo account in there they will be able to see your progress (how much XP, how many new skills, how many strengthening exercises, etc.).
Have her friend you on duolingo if she has an account. She will be able to see your daily, weekly, monthly, and all time progress, I believe