Is it ok for a 22 year old guy to not have a girlfriend?

A few of my co-workers have found out that I have been single since high school (I don't know how since I don't make a habit of discussing personal business in the workplace) and they keep pestering me about finding me someone so I can get laid. The thing is I don't care much for dating, I'm perfectly content being single. I tend to dislike excess emotional attachment anyway. So two questions: one, is this normal, and two, how can I get my co-workers to shut up? Whenever we're together in a more quiet setting, all they do is talk about , cars, and more , and then they wonder why I avoid them outside the office.