Next she's gonna want an internal geared 3 speed hub!
I remember building up a little 12" drive wheel like for my first born when he was 5 (back in '91) as he wanted to "go faster" on his little bike!
It was a hoot to see him ride on that thing!
Not too funny to see him crash though - Busted out his 2 front teeth. Good thing they where just the baby teeth!