How can you watch that and not smile? Too easy.
Make sure you’re the first person to do this. Others will try to dance with her afterwards, but they’re just biters.
And for God’s sake, get to her early in the evening. The last thing you want is to lose your opportunity because the reception has gone on past her bedtime. Unless her mom has allowed her to eat copious amounts of cake, she could very well fall asleep on you before the dancing starts.