TO SEW OR NOT TO SEW
So you want to be a Fashion Designer and you're wondering if you need to know how to sew to be a good one. Good News, You Don't!! Now you can breathe. You can totally be a fashion designer without knowing how to sew. As a designer, your job is to be a creative thinker. Think about it this way, If we were building a house, you would be the architect and not the contractor (That's my job as a pattern maker and seamstress!) Your job as a Fashion Designer is to be as creative as possible in a way that helps your brand or whatever company you end up working for.
IT DOES HELP
BUT! While sewing is not a requirement to be a successful fashion designer, understanding the basics of how to construct a garment is. You need to know what goes into making a pair of pants, shirts, skirts, jackets, etc. You don't want to design something that cannot fit on the body. (Unless that's your intention, but that's a whole other conversation!)
The truth is that the most important part of being a fashion designer is that you have a creative mind that can think outside of the box. You don't need to know how to sew. You can design your garments without ever having to touch a sewing machine. That wouldn't make you any less of a Fashion Designer. Plus if you sewed the garments by yourself, where would that leave people like me who do not much care for designing but absolutely love sewing and construction?