Raising teenage grandkids is a challenge. My twin grandkids were 15 years old when they moved in with us. At this age, kids are just discovering who they are and who are their real friends. Unfortunately, my granddaughter discovered some of her friends weren't really friends and other acquaintances became friends. We also had the twins eat dinner with us every evening because kids who eat with their families pick up on family values, news, and do better in school.