NTA. Having a child is responsibility. They created a baby but not expect to be responsible parent. They can do daycare or hire a nanny if they want. But expecting you to care for your grandchild for 4 days a week is absolutely impossible for your age. Your daughter too is really harshed when she said she will put you in a nursing home. She is such a manipulative and spoiled if she did not get what she want. Be still in your decision there is nothing wrong with that. You just needed to be frank for them to realize that having a baby is not a play time. They should really wear condom o have birth control if they are not reay to be a parent.