I want to go to school and become a nurse, but I have no education whatsoever?

Okay, so as of right now, I am 19 years old and working close to full time at a grocery store. I was home schooled, but my mom never taught me anything. I'm not stupid, though, I just wouldn't be able to follow grade 12 work. I don't have a high school diploma or anything to show that I graduated. Problem is, I want to become a nurse, and now that I am 19, and will be already 20 years old next year, I would like to start trying to make something of myself. This is all very discouraging, and it isn't even my fault. How do I fix this and get started on becoming a nurse?