Legal Question in Family Law in Florida

It will depend on a lot more information than you have provided. First, where is the mother? Who has custody? Is the bio father paying child support? is he on the birth certificate. Is there a case on record in the state?

You can always file a Petition for Custody - but I don't think you have standing and therefore your pleading may be dismissed.

On the other hand, you might could file for guardianship if the mother is incapacitated and the bio dad is not in the picture - but here again , there are numerous pieces of information lacking from your question.

Except in the very, very rare case of where DCF or a dependency ("abuse or neglect") judge can't find any other relative or foster parent, no. A step-parent has no "custody" rights over a child. The desires of the child would be irrelevant.