I think it's important to explore your feelings about why you want the switch. There's a big difference between wanting to do it because YOU want it, and wanting it because you're getting messages from others that it's "time". Separate sleeping quarters are a relatively new phenomenon, historically speaking.
Co-sleeping is a very emotionally charged issue for parents, right up there with nursing (or not), spanking (or not), etc., so people tend to get very worked up about it. Listen to them, don't get too sucked in emotionally, but keep your ear out for good tips that feel right to you. There are solutions that fall in between a crib and direct co-sleeping, and there's lots of support and ideas out there on the Internet.
Let me say also that medical students and pediatricians receive next to NO training in breastfeeding support and infant sleep patterns. Much of their advice comes from how they were parented, what their spouse is doing, and other doctors (who may or may not be very well-informed). I know this because my husband is in medical school (and planning on being a pediatric intensivist), and I've heard some pretty crazy (and outright WRONG) information coming out of instructors' mouths.
There is, however, a lot of research being done on infant sleep, with all the attendant controversy about research methodology. James McKenna at Notre Dame runs the Mother-Baby Sleep Laboratory, and his research seems to suggest that cosleeping protects against SIDS. Your baby is beyond that fear, for the most part, so I suppose that's not a big factor. Other research supports babies sleeping alone. For nursing babies, they certainly may not need the caloric intake, but they may crave the comfort and closeness of the breast, which is a legit reason to offer it in the middle of the night. Remember that for babies, everything is still very new, and they find comfort in your scent and milk. By the way, many breastfeeding professionals (IBCLC's and lactation educators) believe that babies do in fact need the caloric intake of milk at night, particularly if you're working outside the home and leaving the child in day care.
In other countries, families cosleep quite happily for quite some time into a childs' life, and I can't tell you how many of my friends, with children well into the elementary school years, find themselves sharing their beds in the middle of the night.
That said, it is also your right and choice to have your bed to yourself. Doing it in the gentlest possible way will help both of you. Listen to your instincts - they will guide you.
My son coslept for quite some time, and continues to love it when I offer occasional cosleeping (he's 7). The kiddo snuggles close all night. My daughter actually resisted cosleeping, and only sleeps comfortably in her crib. This was a shock to me, since I am so in favor of cosleeping, and I mourned the loss of a cosleeping relationship with her. But each child has a certain temperment, and asks for different things from us as parents. Our job is to meld their requests and our needs as a parent.
Good luck to you! It's not easy ....
Oh, and may I suggest any book written by William and Martha Sears? While they're very in favor of co-sleeping, they do offer suggestions for easing baby out of your bed, should you feel the need.