At 40 you really are a grown up and Narcoossee's will definitely fit the bill. It isn't too stuffy that kids can't be comfy there too. For the kid in you get an 8ish ressie. You'll catch the Electric water parade going by in the 9pm hr then Wishes from the deck later in the evening.
The food and service at Narcoossee's are absolutely fabulous. Wish I was heading back there. Be sure to have the bday noted in your reservation, you might get a treat!
As for some menu highlights: Surf & Turf (substituted scallops for Turf), YOAMD Almond Crusted cheese cake for both the presentation and taste, crab cake appetizer and I think my mother had a seafood soup/bisque.