Age Old Solution for Men

What's the difference between girls aged eight,18,28,38,48,58,68 and 78?

At eight you take her to bed and tell her a story.
At 18 you tell her a story and take her to bed.
At 28 you don't need to tell her a story to take her to bed.
At 38 she tells you a story and takes you to bed.
At 48 she tells you a story to avoid going to bed.
At 58 you stay in bed to avoid her story.
At 68 if you take her to bed , that'll be a story.
At 78 What story? Whose bed? Who the hell are you?