FB/ co-worker relationships

I want to defriend a co-worker (female, I am also a female) on Facebook for various reasons. I know how easy it is to defriend a person on FB, but I also have to work with this girl 5 days a week, and I know eventually she will either call me out on it in front of everyone or make my work life even more miserable. Does anyone else have experience with this situation and how did you handle it? I do like my job but have considered leaving partly because of her. I don't want her seeing my posts. I quit having personal conversations with her. I am friends with several other co-workers that I don't mind seeing my posts. Suggestions?