A Mechanical engineering degree provides many options for what you may end up doing. There will be an opportunity to specialize in the last 2 years of your studies. In my career I designed products and created manufacturing processes to produce them. Later I was able to sell technical systems to international customers as well as lead engineering service and manufacturing companies.
Friends of mine with mechanical engineering degrees are doing everything from being a physician to building nuclear power plants to designing heart assist pumps.
Mechanical engineering is a versatile degree that teaches you how to solve problems and is valuable and desired for many jobs. Good luck with high school.