Parents! How upset would you be?

Ok, my boyfriend asked me to marry him and i've been thinking long and hard about it and have decided I want to go through with it. He wants to go to the courthouse and do it. I am excited but at the same time I am kind of scared because my parents have not met him yet, and also because I am thinking it would be best if I did not tell them until afterwards. I say this because I know my family and if I tell them beforehand they will be against it and try to talk me out of it because I am still in college. I really love this guy and want to spend my life with him. Since I have been with him I don't talk to anymore guys, I have been more focused on my studying and I don't party all the time anymore. I am just ready to commit to him, but as I said my parents would be against it. I've tried to take him to meet them but they don't want to meet him because of...other issues i've had with guys in the past. Anyway parents I know you would be upset but could you accept it?