Don't know details about birthday options, but we were first able to go to T-Rex when it first opened. DS was 8. They went out of their way to make ds feel special (with no special occasion). We had a great time. DS is not a fan of kiddie food, wanted the steak, so I'm not sure of the kiddie menu. But the steak, vegetables, waffle fries were great. He got a special drink and purchased a dino straw in the gift shop prior to dinner. He purchased a build a dino after dinner. We were encouraged to explore the restaurant and the gift shop and the build a dino areas. I think it was great fun for a boy of any age. One of our favorite Disney memories. Sometimes I feel that we are surrounded by princesses, TRex is a nice balance to that. Last trip we were only able to stop in for a minute. This trip we will dine there again!!
Your ds will have a great birthday there!!! Great choice, IMO!!!!