Have an Answer?
The best advice I can give is to ask yourself what do you love to do so much that you would do it for free just for the experience. Answer that question and you will find the answer to what is your niche.
For me it was an addiction to print. I loved reading and writing and just followed the course where my addiction would take me in the field of writing. I also had an insatiable curiosity on how things worked. So I majored in English which led me to my career as a freelance technical writer. In this field one must know how products work and how to use them before it is written as instructions for the users of the product.
When I was in college I actually took an entire course catalog and highlighted all the courses that interested me, then looked up the descriptions and narrowed down my choice of major by elimination. After school I looked for jobs that would give me lots of different opportunities to learn new things and learn about different careers. The most important thing is to be curious, continue to look for opportunities, and find good people to learn from.