I want to change the jurisdiction of my case from MD. To GA. When is this possible?

That's up to the courts. It may vary. Are all parties now in GA?

If all parties in the case are in GA now then it will probably be done after you petition the court to change jurisdiction. However, if one or more of the parties involved still resides in MD then it isn't likely that the court will grant it.

And in GA they will have to have lived in the state for 6 months normally to be considered legal residents of the state in court.