Once again, follow the money. If the grandparents are getting money for you to stay with them, or you are being counted as a member of your mother's household in some way that benefits her financially, they will absolutely not give up on keeping you (and your baby when it comes) at home with them, at least with grandparents. Many times teens who are 16,17, feel they are independent adults, but they are not completely familiar with their family's sources of income, and do not realize that their parent or caretaker may be receiving benefits specifically because they live there.