I'm not sure I'd say it was inappropriate, as there isn't any swearing and if I remember, just one kiss.
But the story is oriented towards young teens. It is story about a teenage girl who is rebelling against her mother (she dresses rock 'n roll ish, has a bad attitude, etc). They get into a big fight at a restaurant, and wake up the next morning in each other's body. From then on it gives the message about how each should respect the other's "lifestyle" (for lack of a better word??)
I went with DD8, and as much as she said she liked it, I caught her getting bored at certain points. It does have it's amusing parts, and I probably enjoyed it more than DD.
IMHO I'd say 5 is probably a little too young. It is better suited for 8-14 yr olds. My advise - wait to rent the DVD.
I hope this helps.