For my kids parties we usually have sandwiches - I buy sandwich buns, Turkey and Ham from the deli at the grocery store (you can add cheese and put the sandwiches in the oven until the cheese melts) and then we usually have potato salad or Chicken cashew salad, chips and dip, veggies (carrots, cauliflower, peppers) or fruit (whatever is in season is good). If you keep it simple it is always easy.
It doesn't need to be fancy - remember that people are coming over to celebrate your daughter's birthday - not just to eat your food.
One other thing to remember in response to previous advice:
You are inviting people over to your house and unless it is a planned potluck it is not ok to ask people to supply the food for your daughter's party.
Have fun and Happy Birthday to your daughter.