How do I prepare for life?

I have grown up in foster care and in 3 months I will turn 18 and be forced out on my own. I always tried so hard to get good grades but I realise now this hasn't helped me much at all. I can do algebra and know about history but I don't know the laws of my country or what taxes are and how to pay them or anything else practical. I can barely cook and I don't know my rights or how much it would cost to raise a child or anything.Two years ago I had a nice foster mother who helped me write a resume and get me a job and I'm grateful I was able to get one and I've saved almost every penny but I know it's really not enough. In just 3 months I'll have to buy or rent a home. I don't know how to do this or how to get a loan (or if i'll even get approved for one). Where can I go to get basic life knowledge? I haven't been able to learn from experience unfortunately. I've been through horrible things but they weren't the right kind of things, they weren't experiences that made me wiser and better, they were terrible things that no child should face. I am frankly terrified and stressed about my future, and angry that everybody made me think school and grades should be my first priority and that my life would be ruined if I couldn't tell you what X equals or how WWII started. My life seems ruined now and it's because I have no idea what I'm doing and spent my life focusing on grades and not learning things I need to survive in this big cruel uncaring world. How do I prepare?