Creating a clothing line is a wonderful idea. A great start is to write down what you want to do with this clothing line. Do you want to make custom clothing for each customer? Have your clothes available at retail stores? Design for Gap or Sell your designs to Nordstorm? Have an online store to sell your clothes? Do you want your clothing line to be a hobby or a business? Write these questions & answers down in a notebook. These questions & answers will create a road map of your plans. This road map will show you where you are today and where you want to achieve in the future. It will also begin to help you understand how to reach your goals and/or more questions to ask. You can create these road maps for any type of career you have in mind.
It seems you are trying to pursuing two different career options (clothing design & business admin), and they may work well together. If you are trying to create a clothing company, business admin will help you understand how to streamline & organize your company. If you want to pursue fashion/clothing design, there are also design schools that can help you master the needed skills so when you network with people in your design community, you can speak the design language, understand fashion trends, patterns, sewing, fabrics etc.
Reach out to your guidance counselor and ask him/her about colleges that will help reach your goal. Show them your road map of careers you are thinking of pursuing. Tennessee State may be a great fit, and/or you might find a few others that will also help you reach your goals!