Every problem has a simple answer. In math, even if your equation is complex and looks advanced, there's a right way to do it, and a specific answer. Math follows a set of rules that everyone has to go by. In other subjects, and in social situations, there's not a defined right or wrong answer, and the answer could very from person to person, and how well you did could be subjective. In math, there are defined rules, allowing me to come up with a solution I can be confident about.
Math has changed the world. Earlier societies used math to study astronomy and physics, and we have built upon their discoveries to get where we are. Math is used nearly everything, from things like physics and chemistry, to art and architecture. These subjects can often overlap, such as how an architect has to think about the physics of what they design, but can often be artistic about it. A big part of technological advances is mathematical, and programming is also based on a set of rules like math is. Technology is such a big part of modern life, affecting not only our social and professional lives, but healthcare and accessibility for people with disabilities. An understanding of math will always be important, no matter what someone's interests are.
When I tell people I'm a marine biology major, they often tell me, "Wow, you must be smart!". I got the same response when I was considering other majors, such as mathematics and geology. Before I decided on a major, I always told people that, while I wasn't yet sure exactly what I wanted, I knew I wanted to go into a field that involved a lot of mathematical or scientific thinking. I have loved math since I was a child, and my mother first taught me how to multiply using french fries, before I learned it in school. In elementary school, I thrived in math, earning an award from my teacher in 5th grade, and being placed in advanced math. Even I think math can be difficult sometimes, but I know if I try, I will understand it, because I can trust that it will follow a set of rules and make sense. When I finally understand how to solve a problem, I feel like I've achieved something. People may think I'm smart for my choice of major, but I do not think that, if I am, that that's what makes me smart. I chose my major because I love math, and it just makes sense to me.