Unfortunately, I cannot answer this as you are the only person who can truly make this decision as you are the one who has to stay true to yourself.
I will say this, EVERYTHING is BUSINESS. Even Non-Profit organizations are in the industry of making and collecting dollars. how they distribute it is neither here nor there.
That being said, I double majored and instead of going into education or criminal justice, I stuck with my Business degree as I figured it would serve me well from a broader perspective. You will pick up knowledge on whatever route you take, just know that following your passion for fashion designers can take you only so far as you eventually will need to either work for someone or monetize your designs to become profitable (both a business degree will help with). On the flip side, the reverse is true. I cannot advise you one way or the other but I do believe you could apply your business degree in many more fields than you could your fashion degree.
But I have seen people do amazing things with both, and in conclusion I think you are doing the right thing by pursuing an education bottom line :) Good luck!
Business is a broad topic with varying applicable degrees and jobs. It will help you if you choose to start your own (fashion?) business one day. Fashion design is a very targeted business that requires specific skillsets. I recommend starting with a fashion design course or internship where you can learn and see if you'd be interested.
Do whatever brings you the most joy. If you truly love designing, it will show in your work. If it's just the start of a new interest, try a few courses and see where that leads. If you know anyone in either field, talk to them about their journey and what they like or would have liked to do differently.
If it’s a question of pursuing fashion or business as a major/focus, the reality is that you don’t necessarily have to choose one or the other. The question may be instead: which course of study will make you more successful in the long run? It’s been shown that people are more successful when they are on a career path that they truly enjoy.
If you are a fan of fashion and feel you are good at it, then you are likely a creative person. Business may not be considered a creative field but it can be, depending on what your business is.
Most companies will initially hire you based on your education but, after you have worked for a time, there is less focus on your education and more on your experience. Even if you decide to go toward fashion now, you can build your business skills with the roles you take in the fashion industry. The same is true of business: if you decide to get a business degree now, you can leverage that experience in the fashion industry or in starting a fashion business of your own.