Sometimes I just feel like I want to have more fun before settling down even though I love this girl, what should I do?

Grow up. You may love her, but clearly you need to do more emotional maturing before getting into a committed relationship. It's not fair to you and certainly not fair to her otherwise. Sometimes though that growth can be gotten by looking at what you are going for. Is it that you want more fun, or that you are scared of the relationship?
You are not in love. You are not ready to settle down. You are not truly in love.