Independence of a Child

Why is it so hard for a mother to let her daughter go out into the world? My daughter is 18 1/2 years old and she has really started this independence thing. I don't know how to handle it that well. Problem I have been having is....she only wants my help when it's something she can't do. Other than that, she had rather I stay out of her personal business. Do you think she will ever get past this? We use to be such good friends.