Who gave her permission to grow up?

My oldest wants to move out to stay with my brother and his wife in the Seattle area and take care of her very premature, still immune compromised cousin, so my brother and his wife can both go back to work full time. She is almost 21, she can make her own choices. I'm going to miss her, as she is the only one of my big kids who has a drivers license. It's going to be a pain to drive #2 to class every day next semester.