This is not a time for anger, blame, shame or punishment.
If your daughter has had no prior boyfriends or flattering attention from boys, she may be very reluctant to give up this relationship, despite the age difference and logical explanations why it's not a great idea.
She doesn't need to hear things like, "You know the only thing a 17-year-old boy wants with a 14-year-old girl, don't you?
" Knowing why she feels a need to keep this or perhaps any involvement with boys a secret from you will be helpful in talking this over with her.
When she got home we asked her if she had given out our home address and phone number to any boys and she said yes. My husband and I got married when we were 18 and had our daughter when we were 17. You do have reason to be concerned about a relationship between a 17-year-old boy and your 14-year-old, eighth-grade daughter.
Seventeen-year-old boys are indeed at very different developmental stages -- intellectually, socially, emotionally, and sexually -- than 14-year-old girls.