Oh dear, are you in for a BIG surprise.
When you turn 18, you are completely responsible for your own fine self, and everything you do, probably for the first time ever.
Yes, you "may" have the right to do a lot of things, but you will not likely ever be free to do "whatever you want". There will *always* be someone telling you you can't, or some good reason you can't do everything you want to do.
You will need to go to work, to school, to pay your rent, to wash your clothes, to get gas in your car, to pay your insurance, to pick up your kids, to speak to their teachers, to meet with your boss, to get medicine for your spouse, to vacuum your home, to mow the lawn, to shop for food, to clean the fridge, to attend a funeral, to go to a work conference, totake a continuing education course.
There will ALWAYS be reasons you can't do everything you want, although there will also be opportunities you never dreamed would exist. Trust me, being 18 doesn't make you free. It makes you completely responsible for everything you do, and everything you need. You may not miss school, but there will be something different to fill your days.