Highschool is just the tip of the ice burg! You have so much to offer the world and you might not know which direction to go but just getting out and talking to people about things you like to do is a place to start. If you have a part-time job that you enjoy...ask questions about the business and how certain aspects work. If there is a brand that you like, you can always call that company and ask for an 'information interview'. It's not quite a job interview its more of a conversation about how the business works and an opportunity for you to share what you like about it. You'd be shocked that that meeting might turn into something for you in the future. Maybe even an internship! Good luck!
If you go to college the education aspect of life remains the same, however the people and lifestyle changes vastly. If you decide to live on campus, you are introduced to a lot more freedom than you had staying at home, you have a lot more responsibilities, in terms of food, laundry and creating your own schedule. You meet a lot more new people, from different parts of the world, and start making connections with people with different mindsets. It helps you grow.
If you start working immediately, then life changes a lot. You aren't paying an institution, an institution is paying you. You have to work for someone else, adjust, and deliver based on someone else. Ask to take days off, and plan your schedule around the work environment, it takes a couple months to get adjusted but the satisfaction of providing for yourself is incomparable.
Hope all is well! Yes, life after high school is different, but in an exciting way! There is so much more positive experiences available for you to enjoy, connections to make, and overall growth to undergo. You have more responsibility and dictatorship when it comes to your post-secondary career whether that means attending college or entering the workforce. There are so many great options for you to look forward to!
Remember, what is most important in your post-secondary career is happiness and you are the only one that can define your happiness! This is your life and you are the only one that can live it. It's okay if there are trail and errors, setbacks, or revision happening in your life after high school; that's normal.
I wish you luck in your future endeavors and I hoped this helped!