A lot of colleges offer great courses like costume design, art/sketching , fashion design, etc. This all depends on your major and what field you want to get into. Costume design courses are very beneficial! A business management course could also be very useful to help you grow your business and personal brand.
Talk to local artists and they may be able to help you with finding an internship! A lot of college's help place students in internships in the field that they desire. Take a stop by your counselors office and they may have a way to help further guide you!
Every college is a little different in what course you need to take for Fashion Design. If you go to a school like Parsons or FIT they have a very structured academic program with Fashion Design as a main major. If you go to a school that isn't as structured like I did most likely it will fall under Family and Consumer Science and you'll have to take the elected course work that's provided under that major. In all it depends on what school you attend.