Is it okay for me to move out from home after I'm 18?

Well, I can only suggest that you consider dorming at a college for four years before dreaming about making it on your own in the world without an education. It is simply too expensive and unreliable for those who are educated and gainfully employed, let alone a teenager starting out in the world. If your home life is not ideal, you need to weigh your pros and your cons.

What do you like about being home?
Don't say "nothing!"
Your parents/guardians and/or siblings have many perks. Maybe it is easier to eat when it's a group meal. Perhaps you will miss the noise. Some people really struggle with their desire to move out and their inability (or lack of practice) to be alone.

What do you hope to achieve by this move?
Sometimes family values are a major conflict for a young person. Maybe your parents are very different than you, and it helps to create some distance for the sake of getting along better!

Whatever you decide to do, consider your social life and responsibilities. Keep in mind that you will be in charge of buying everything and providing for yourself, food and heat included! If you're not financially ready or employable, don't bother making your life miserabl by adding unrealistic expectations to your young years.

If you dorm, it may be the best time to practice being independent. For four years, you can have a nice balance between sustained living and being independent. At times, you will be completely on your own, and at other times, you will feel very happy to share with others in being grown-up. There is no reason to miss out on the experience of dorming. The student loans and costs you may have in order to dorm are a better investment than paying rent on your own without getting an education in the end!