Moving in together is a big step in a relationship. On the other hand moving in does have it's perks. It's a good way to save on rent and expenses. Your sexual activities may increase, and you can take your relationship to the next level. Cohabitation can be construed as a sign of commitment and joy.
I'm not personally a proponent of cohabitation before marriage. If you asked for my advice, I'd tell you not to. There's plenty of empirical research out there to suggest that it might not be the greatest idea. But you don't need to reduce men to sex-starved lunatics (or women to desperate shells who will whither and die if they don't get a ring) to get your point across.
Over the past decade or so, I've found there are a few common pitfalls that women who want to get married inadvertently fall into, and which decrease their chances of getting married while they're still young enough to walk down the aisle without stopping for breath. One of these pitfalls is living together before marriage.