Congratulations on your huge accomplishment! I am so excited to see where this life takes you! You're going to be getting a lot of advice in the next few days, weeks, and months, and I wanted to throw my two cents in for what its worth.
The best advice I can give you as you complete high school and move on to the next big steps in your life is: "Don't be afraid...you're going to be OK." It may not make sense yet, but give it some time. Go out there (where is "there" anyway) and try things, make mistakes, and take chances (the safe, life affirming kind) trusting that it is highly likely that you will become a better and more enlightened person because you did. Your plans, interests, friends, finances, health, all may change, but remember, it's all leading you down the same path, and chances are very high, that it will all work out. In fact, change is what molds us, what teaches us, what allows us to grow, what exposes us to opportunities we never knew. You may be changed too, but as long as you keep moving forward, you will most likely end up where you are meant to be. There are so many pressures and expectations which you may or may not be feeling yet, but I want you to know YOURS is the loudest voice you should listen to. Yes, many have gone before you, many have sage advice (I mean look at me, right here, giving advice) and many can set you on the path for great success, and it is wise to listen. However, if you're not sure what you want, if you don't love the thing you thought you would, if you get homesick, "Don't be afraid, it's going to be OK!" Don't feel like you're obligated to stay on the same path you designed - with minimal information and life experience - when you graduated high school. I think real happiness is obtained when we feel that our passions and our opportunities for success collide. And, sometimes it takes awhile to figure out what those passions are. I would say we learn more from trying and failing than doing what is safe. The reward often feels much sweeter when we take (calculated) risk and succeed!