Need Relationship Advice

Hey guys. I don't quite know what to do. I have a great girlfriend, she is willing to pick up the tab, I enjoy spending my time with her yet the problem is, I am not sure she is the one. I am 19 and I truly love being with this woman, yet I find myself wishing I were single...Longing for the time when I was on the "hunt" for women. My problem is, I am not sure if I am ready for a relationship. I have already told her I love her, yet I don't want a relationship. That is the main issue, I would like advice on that front. The underlying problem is that when I am single I want a relationship, but when I am in a good relationship I want to be single. I need advice. Please help