In fable 3 if you choose to be a lady your a princess and if you choose to be the other thing your a prince.
Until release we don't know the reward for success of the MQ.
ATM we know you're stuck in jail at the start, that most likely you can create your own back story.
That you are a dragonborn and are fated to do great things.
So TBH you may end up as a princess or a queen, but at the start you can pretend to be whatever you wish.
Whether common, noble, princess or warrior, mage, knight.