I do know of an instance where a very humble sister appoached the elders and requested the opportunity to get rebaptised because she did not feel she was baptised for the right reasons and this was permitted. This would mean tht her original baptism was annulled. However the situation was different to yours in that her purpose was to get rebaptised, she was still attending meetings, she had not been Df'd or Da'd.
One thing I do object to in the baptism questions is the questions relating to DF'ing are extremely limited and do not actually address the area of disagreement with the religious doctrine. They are couched in such a limited way that someone getting baptised would never envision a time when those scriptures would apply to them. As such, people getting baptised are not made fully aware of the consequences of their decision and therefore are not making an informed decision when they take the oath. After all if a minor is asked questions about fornication what level of understanding would they have about what that means? If you were a minor when baptised I would ask a lawyer to write to the society since you were not old enough to sign a contract you were not old enough to make a verbal one either. Hoever once the decision is made it is hard to get them to annul it.