Job well done. I took my CFI checkride in a Beech Sierra about 25 years ago. I had never flown one until the day before the checkride. I stayed up all night to study the airplane and its systems, speeds, avionics, etc. It was the hardest checkride I have ever had ( private, IFR, commercial, multi, multi IFR, CFI, CFII, Multi CFI) I was about an hour late due to weather and had to request a special VFR clearance to get into the airport. after a long flight. I later found out that the FAA examiner knew the airplane tail number and had been listening to my radio technique. He was actually observing me ( sort of ) before I even arrived. I was scared to death at being in the FAA office, sort of like being in a lion's den. The examiner sensed that I was nervous at the beginning and went to get me a cup of coffee. He took a very long time ( on purpose I think ) which gave me time to relax a bit, clear my head and transition from difficult flight to teacher/checkride mode. Once we were finally in the air, he pretended to be a student, sometimes with 0 hours, sometimes with thousands of hours, and anywhere in between. After what seemed like the checkride that would never end, I was awarded a CFI certificate. There was another guy there the same day taking a CFI checkride in a Piper Arrow, he did not pass.
Things I would do different.
Make the flight the night before, get a room, get rest.
Be on time, its just part of professionalism.
If possible, use an airplane that you have a LOT of time in, know every screw, every switch, every number, every scratch of that airplane.
Remember, the examiner is not a monster. He/she is a human, there to do a job. No more, no less.