Nicole, I'm choosing to live alone next year when I start PT school, but under very different circumstances. I'm staying at my undergrad institution, in the same complex, just moving to a 1/1 instead of the 3/2 I'm in now. Because I chose the cheaper school tuition-wise, I can justify spending an extra $100-200 a month because that will never even come close to hitting the extra $30,000 in debt I would have had at the other school. Plus, I just got a puppy who tends to get weird around people she isn't familiar with (and I'm hoping that will change the longer I have her, but I wouldn't want to impose those behaviors on an unsuspecting roommate).
I have some anxieties about living alone, but they're far outweighed by the anxieties I have about living with people I don't know. And for my personality, I think living alone will work out best.
If this is really your first time living on your own as you indicated, it might be useful to live with a roommate for one year at least just to have the experience of compromise when it comes to living with others (God..my student affairs background is showing...). But then again, most people knock that out in their first year of undergrad when things aren't as rigorous academically.
Another pro to living with roommates is that if you're moving to a new area, you won't feel as isolated when it comes time to get to know the city. You'll have someone with you to awkwardly bumble through it with.
I don't know. You could go back and forth all day. It just comes down to what factors are most important to you.