How to prepare girlfriend for an endurance race?

I managed to convince my girlfriend to do an endurance with me, but she is very new to it, so I will teach her all I can. Therefore, I am also asking you, what do you think is essential or worth mentioning that might go under the radar?

Our first endurance race is going to be a 2 hour 40 minute multiclass race at Road America in a Mustang GT3. I'm gonna marry her.