My exgirlfriend's 5 year old daughter (I will refer to as A), who I have raised since birth but is not my biological child, lives with me in Florida. A and I recently moved to a different county in Florida with her mother's consent. Her mother gave me a power of attorney for care and custody so I could deal with medial issues, school, etc. A does not know that I am not her biological father and we would prefer if she didn't until we were ready to tell her. Her mother and I both want to change her last name to my name. Her biological father is not on the birth certificate and is basically unknown. Unfortunately, it could be any of several people and her mother does not know their full names, much less the locations, of these people.
How difficult would it be to change a minor's name in Florida if the biological father is not on the birth certificate and is unkown? I am preparing to register A for kindergarten and I would like her to have my last name when she enters school. Any advice would be greatly appreciated.