Me vs. children

Talking about DVD`s, CD`s with a 7 years old girl.
I told her about the pick up player (never heard of that) and about audio tape.
Never heard of that, too?
No, she said.
Never seen an audio tape? I said describing her one.
No, she said again. And then:
" I`m only seven!" (just like - I`m only seven, doh!)

I`m so old...