My parents are forcing me to go to college. How can I make them understand that I don't want to go?

Actually at first before I graduated high school I wanted to go to college. I applied and I got accepted to a good university. The problem is that my parents told me that they weren’t going to help me pay for college. They said that they think that I’m sheltered and spoiled. They said that I’m an adult now and I should work my way through college like other students. Even when I tell them that I don’t want to go to college they get mad and yell at me trying to force me to go. The problem is that while I was at the local library I started getting clients for my graphic designing freelance service. The library has free computers with all types of software and a recording studio. I’m cool with a lot of local music artist in my area. They pay me to make graphics for them and to make beats and record their music. One of my friends even let me borrow his camera so that I can charge artist money to record their music videos. I’m making pretty good money. Why are my parents still forcing me to go into debt by going to an expensive college? How can I tell them I don’t want to go? I don’t think it is worth the debt when I’m making good money now.