3 year olds and younger children like to nibble. These dishes can be set out at their serving table so they can pick what they like to eat. Lots of times they only take a bite or two!
For the kids:
Fruit diced in bite size pieces on separate plates to be taken and eaten as a finger food (kids that age usually do not like things mixed-grapes, watermelon, melon, pineapple, banana, strawberry)
Cheese tray (bite size pieces-string cheese, cheddar, deli american- cut up)
pickles/olives
cracker tray-ritz, club, goldfish, pretzel
smokie links in crescent rolls (another poster mentioned--my nephews love these easy to have pre-made and ready to go in the oven)
rolled up turkey lunch meat
Dessert: if you do not like cake, kids usually love cookies with frosting and sugar sprinkles on them. You could frost cookies (home made or store bought) and use different brightly colored sugar sprinkles for decor.
All of the above can be made festive depending on dicing technique and the dishes they are served on all fit for a princess!
For a beverage, I would stick with water or pink lemonade. You can make fun ice cubes by freezing a gummy bear or two in them. When little kids run around having fun at a party, sometimes carbonation in pop or milk does not sit well in the tummy. Serve the water or lemonade in a pretty princess glass you can get from party stores with a brightly colored straw.
If there are adults at the party, have some fruit, chips and a party sub for them. Some cookies or brownies too. You can make your own party subs if you want to be creative. Get the big long loaf of crusty bread from a bakery or panera, cheeses different lunchmeats and assemble. You can have them sliced and waiting on a platter, with sides of peppers, lettuce, mustard, mayo, italian and other sub toppings so they can dress them as they want.
Whatever you decide, have a blast!!