I’m only 17 myself so I can’t speak on it much, but I want to reassure you that it’s okay to not have it all figured out. Most people don’t have it figured out. I don’t have it figured out. There’s no cut-off age for getting a driver’s permit or license, getting a job, or going to college. In fact, many adults will wait on doing some of those things or even never do those things! Rest assured, you can go at your own pace and do these things whenever you’re ready.
If you’re going to be a junior in high school this year you will likely take the SAT on whatever day your school has scheduled it, look on their website or calendar to find the scheduled dates. You take it completely free on the scheduled day first, then you can retake it later on if you want to get a higher score (but you’ll have to schedule it and pay, the College Board website or your school should tell you how to do that!)
For SAT practice, you can take practice tests online and watch YouTube videos covering topics in it and how to answer well. Don’t stress over the SAT too much though, you can always retake it and some colleges don’t even care about SAT score when you apply.
For jobs, look on YouTube for videos on how to do job interviews. Then look at what places are hiring near you, usually they’ll have information on their website or you can ask someone in person (an employee or employer/manager) for a job application (if you have the confidence to ask in person) Looking up how to set up a little resume can also help. You can add volunteer work you’ve done or small jobs to it if you have that kind of experience.
For getting your driver’s license, you can look into whatever driving programs they offer in your state/country. Look online or at your school. You can take classes in person or do an online course, and practice physical driving with your parent or guardian. There’s no deadline for when you have to get your permit/license btw. I didn’t get my permit until I was 16 (almost 17) and I probably won’t get my full license until I’m 18. Just practice and go at your own pace, and you can take the test for your license whenever you’re ready.
Overall, don’t stress too much. You’ll grow and learn how to handle these things. It will take time, I promise you no one has it figured out the second they turn 18, but over time you will learn. :)