For those people who are confused with the story "How To Train Your Dragon 2" both Kelly, Astrid, and Hiccup are 20 years old. I forgot to put this on the prologue but there is a curse for teenage Viking parents when they either have a daughter or son they stay the same age that they are until their son or daughter turn the same age as they are and they grow up together as that same age. I'm so so sorry to those who were confused