Conversation with Blondie

While changing the earrings of the Blonde one tonight (who is still a bit squeamish)

Blondie: (said with much drama) From the bottom of my heart, will you please be gentle with me? I'm a sensitive woman.
Sophie: You are not a woman yet.
Blondie: (giggles) Yeah, I know but it sounds better like that.

Then, a few moments later the two of them are talking like Valley Girls, and they know they are talking like Valley Girls. How the hell do two kids born in 1998 know about Valley Girls??