My father is 82... and although not racing or going to the track, he still goes out FOUR nights a week in the summer( mon, tues, wed, sat) with his '63 Impala.... a car he's owned since November of 1964.... My mother isn't a car person at all, but she tolerates it.
make her a deal, for every car related thing you do( show, race) you have to do something she wants to do.