Just relax. College begins a lot like high school, the only difference is that it costs a ton of money, and you can choose whether or not you attend a particular day's class/es.
If you get to your Junior year of college and decide you want to change majors....do it. It's ok. Make sure you are happy with the major you choose, don't choose it because you think you should.
As you grow up you will realize that pleasing your parents, friends, coaches, etc isn't what is best for you. Each decision you make needs to benefit you only. If you are not happy with your choices, then the people around you won't be either. In the same vein, you will also realize that it doesn't matter what other people think about you, and you will start to become comfortable in your own skin.
Here is a secret....nobody feels ready for the 'real world' and everybody wishes they were a kid again. Being an adult isn't all fun, but it's not all work either. Greater responsibility has greater consequences, and also better rewards.
You are on the precipice of something great and vast...adulthood. Just like the first time you went to ride a bike without training wheels, you will naturally be a bit scared but once you get going and start to trust yourself, it's the best feeling in the world.
Good Luck!