Women want to make sure there isn't something wrong with you...having a previous girlfriend isn't definitive proof of that, but it at least says that another women approved of you for x amount of time.Make up that you had a few girlfriends...like one awkward high school relationship, one college relationship, and then if you want maybe one other one.That is, of course, if the girl you end up dating has had prior experience. There are plenty of girls in their early 20's who have never had a boyfriend, and if you want this girl to be something more than an experience or springboard, then it's better to start off with honesty.If you just want to get laid or gain experience, then yes, make up a story and rehearse it until it's memorized. Don't volunteer information at any time, just be confident in your story should you ever need to refer to it.