Job/Career - You don't need to have it figured out now but here are some options if you're lost. These will vary with how much your parents/family help you out financially.
Community College Degree - If you're going to go to college then go to community college first. That will cover your associate's degree and you can package the associate's as 60 credits towards a four year college. Community College is much cheaper than a four year and the professors are typically pretty much the same, I had a lot of professors that taught at military schools or high ranking medical schools. If your parents are NOT helping with college then you most likely qualify for a state grant, which in my state, covers the entire tuition.
Community College Certificates - If you don't want to go to college then a community college may be beneficial still due to the certificates some of them provide. You can get a radiation technician certificate within 6 months and be around $70,000 a year just from that certificate. Apply this to Paramedicine, Firefighting, Welding, whatever it may be, a community college near you most likely has some certificates that are worth exploring.
Fire Department - A good choice if you're poor. The state/city will cover all your courses and equipment and you can have a full-time job within 6 months.
Military - Stay away, not a good decision if you're lost. You'll simply have four or five years go by, get out with some cash, and still be lost. Only join if that's something you have wanted to pursue your entire life.
Government Jobs - If you're in some of rural area a lot of state jobs have employee needs. If you typically just have a high school degree you're good to go. This is a bit different in major cities due to more people having degrees.
Sleep/Fitness/Health - Get control of that before you're 30 years old and weak.
I will emphasize that you do NOT have all the time in the world. Do NOT take advice from people who tell you that. You're 18 now - and within a blink of the eye you will be 25 potentially in the exact same situation you are today, wondering where to go. Don't go in a rush but whenever somebody tells you that you have all the time in the world think about where that individual is in life and if you want to be in their shoes.
Do not get complacent with the time that you have. Remember to enjoy it and investing time into something and realizing it isn't for you isn't a bad thing, you're just one step closer to finding what you enjoy in life. Whether that be finance or living the woods.
You are also the sum of your friends. If all your friends are losers then you're not a guy with loser friends, you're just a loser. Find people like-minded with discipline, hobbies, goals, people who exercise and appreciate life. You'll find these people in positive hobbies so don't expect them to find them at a bar or somewhere similar.
Same advice goes for the person you date. If you date a loser they will absolutely drag you down and take away time that you can never get back - so be selective, not desperate.