One should not underestimate the domain of the fashion industry as this industry has many subcategories as well. You can excel in a specific niche or you would opt for the entire realm of this field. However, it is better to establish a niche and then solely focus on it. With that aside, there is another misconception that I find demoralizing. If you want to become a fashion designer then you surely would have to learn the art of fashion illustration.
I understand that many new artists or designers take their time to understand this notion but it is better to know this fact before you enter this field. The goal to become an artist is not a far off task as several fashion illustration artists exist that worked hard to reach to the point of worldwide recognition. That is one thing that I want for myself too and I hope to acquire fruitful results from it soon.