Hi Patricia! My daughter is also a very picky eater so I can understand your concerns.
If you decide to get the dining plan, your child will be charged for an adult plan. The reason for this is that the dining plan mirrors the tickets. Since your child is 11, and has to have adult tickets to enter the parks, the dining plan will also be the adult option. You can order from the child's menu if you would like, but it wouldn't be very cost effective for you if you were to buy the plan. Most quick service kid's meals range from about $5 - $7.
However, I will tell you that there are many counter service restaurants in each of the parks that offer entrees on the adult menu that your child may like. There are quite a few locations were you can get chicken nuggets, hot dogs and pizza on the adult menu. If these are things that your child will like, it can pay off for you to get the plan. I would suggest taking a look at some of the menus at
www.allears.net . Click on "Dining" at the top of the page, and then "The Menus" on the left.
I hope this helps you decide if the quick service plan will be right for you. Good luck and have fun planning!