I'm going to bring up an 3 month old incident back up to my dad about his car
How would you bring it back up? Do you know how he felt about your car?
I think he knows I took his car without him knowing at the time.
You should keep it to your self and not create family strife. You should also refrain from doing so in the future.
It's like nothing happened.
If you are over an issue you should leave it be. If you really feel like you need to get it off your chest apologizing might make you feel better.