It usually takes around 90 minutes from the time you get off your plane until your arrive at your resort. That puts you at 12:15. Check in, get to room (if available) and wait for a bus at CBR resort to MK. That is a large resort with many bus stops so allow at least one hour, depending on what section you are in, to get to MK. You should be there with no problem maybe around 2:30, unless your plane is delayed for whatever reason.
So jealous!