I have known a wealth of great guitar players whom are left handed that play right handed. I also have friends whom are left handed who stick to playing left handed as well. I don't believe I have seen a guitar player that is right handed that insisted on playing left handed though.

At the end of the day when learning an instrument you are developing an entirely new skill. I have said this before; playing guitar is similar to that of being an athlete, and is a physical feat. You are doing something that requires your body to move in a motion and manner that it hasn't before. Not only that, but your ears and brain are also working in new ways. All in all at it's basic science, you are taking on something fairly complex that is also extremely rewarding (like most things in life that require hard work.) Keep this in mind and know that whatever approach you take will be a challenge but will shape what your guitar playing becomes. Go with what is initially comfortable and stick with it. Either way will take you to the same result.

Best of luck and let me know if you have any more questions.