Hi, Kristin!
This is a "grey area" question.
Disney's policy states that '"meal entitlements cannot be shared between Guests 10+ and Guests ages 3-9."
However, because Disney calculates the number of entitlements used and does not link the number of entitlements to a particular user, some Dining Plan users have asked a Cast Member at the given restaurant if it would be permissible for an "adult" (10+) to order from the child's menu at the cost of an adult entitlement.
There is absolutely no policy that states that a Cast Member must honor that request, so be aware that you might be locked into the adult plan for your ten-year-old per the guidelines of the program.
Regardless, Disney will work with your family to ensure that even if she is working on the adult menu, she will get a delicious meal made just to her liking.
See you later, celebrator,
-Deborah B.