Insurance company guidelines differ but typically an insurer will require you to list all licensed drivers in your household. If neither your sister nor the other roommate drives your vehicle then you may be able to exclude them from the policy.
Whoever you exclude from the policy would then not be covered by any part of your auto insurance if they ever did drive your car. To find out more about insurance laws in Florida or get consumer help with auto insurance questions you can contact the Florida Department of Financial Services which is the regulatory body for insurers in FL.
If you, your sister or roommate need car insurance, start comparison shopping for Florida auto insurance here with us.