The AYSO approach would be to stop the game, explain the problem to the coach, and have the offender subbed out while she received enlightenment from the coach. Re-start would be a drop ball if the ball was in play when you stopped the game. Pretty dramatic, but without the card. If there were another occurence, then its time for cards. This may be too many layers of kid gloves, but it's built into the AYSO culture.
Cards are a last resort.
Cards are reserved for real hard cases. Your offender just sounds as if she didn't know any better. Fouls are acepted as part of the game. Draw a card, and shame on you. A card indicates that you are a bad egg.