She said she went to the country club to swim often so someone had to drive her...
Which country club? Were her family members? If not who was the member that invited her [snooty Bethesda area country clubs have rather stringent membership rules and are difficult to join - sponsorship board vote after meeting at a party for that purpose, large initiation fee...]
You don't forget the person who regularly drove you to the club. It's unlikely there was a different unmemorable person each time.