You should just order your size from TOMS. Unless you are not sure of your size, the sizes are usually standard and no matter where you order from, you will get the same size. If the size does not fit, you can always return it so as to replace with the right size.
You don't have a store near you where you can try them on? Anyway get your size, that what I did for my girlfriend, bought her size. They were snug at first but they stretch. She loves them, wears them all the time.