You haven't mentioned if there is a theme for your party or what kinds of food you want to serve. I'm going to assume that you are serving the traditional birthday party foods in which case I have listed my suggestions below. Keep it simple and traditional. It might seem boring, but those are the foods that people expect and enjoy at a birthday party. There's no need to do anything crazy or too unusual.
Snacks:
tortilla chips with salsa or cheese dip
vegetable tray with ranch dressing
fruit tray (or fruit salad) with yogurt dipping sauce
bologna and cheese cubes
pretzel rods with cheese dip or honey mustard dipping sauce
mixed nuts
party mints (the colorful pastel ones)
chex mix or party snack mix (found in the chip aisle of most grocery stores)
Dinner:
cheese or pepperoni pizza
toss salad
meatball sandwiches (some people might not want pizza)
chips
chicken wings
french fries, onion rings, or mozzarella sticks
deviled or pickled eggs/beets
pasta, macaroni, potato, or broccoli salad
garlic bread or breadsticks
ham, tuna, or chicken salad sandwiches (make small sandwiches with deli meat and cheese also)
Dessert:
birthday cake/cupcakes
brownies
ice cream sundae bar (with assorted toppings)
cookies (traditional kinds such as sugar or chocolate chip)
cinnamon rolls or sticky buns
donuts
rice krispy treats (also make with fruity pebbles or cheerios)
smores
Snacks: sliced cheeses, meat slices (unless you're a vegetarian, then more power to you), crackers, grapes, apple slices, carrots. Also provide some sort of sugary dipping sauce (you may feel too old, but trust me, this is good for any age) and a bit of ranch otherwise they are less likely to eat the veggies and fruit.
Dinner: pizza, hotdogs or burgers (again, unless you're a vegetarian), but cheese pizza would probably be the best. Give them ranch to dip it in too. Ranch is a good dipping sauce for cheese.
Dessert: Cake and ice cream. Or ice cream pie. Also serve cookies.
Candy: Skittles, nerds, Good n Plenty, Mike n Ikes, etc. No candy bars. Make sure you get a lot of those little things because it's easy to split between a lot of people.
Finger food is a great idea for parties as it is easily handed around, try things like;
Crisps & dip (sour cream & chive, salsa ect.)
Mini Pizzas (or slice up a larger one)
Mini quiches (or slice up a larger one)
Chicken nuggets/dippers
Pasta salad
Potato salad
Cupcakes
Cookies/biscuits
Sandwiches/rolls
Cocktail sausages
sausage rolls
Samosas
Onion bajhi's
spring rolls
mozerella dippers
Bread sticks & Dip
Chicken drumsticks/wings
Potato wedges
onion rings
Tortillas
Scotch eggs
Pork pies
Pizza
You would have to decide what time your part will be. If its mid day serve snacks like burgers, sliders or subs, pizza, sandwich, chips, popcorn, hotdog or the like. If its dinner, more heavy like mac and cheese, meat pie or pasta. Don't forget the cake!
Pizza,
dip
For my 14th birthday party I'm wondering what kinds of foods I should serve? What kinds of snacks? Dinner? Dessert? Candy?