It's bad to date someone who is underage.
Dave who is an adult is mowing his lawn when his neighbor's seventeen year old daughter asks him on a date.
Dave wants to respond to the neighbor's date offer.
Dave tells the neighbor girl that he's flattered but that she should find someone her own age to take her out.
Dave tells the neighbor girl that he'd love to take her out and maybe buy her a drink.
The neighbor girl is happy to hear that Dave feels flattered and thinks it's a good suggestion to find a boy her age.
The neighbor girl is initially delighted but later comes to find that the power imbalance in the relationship is majorly stressful.