Turning 13 years old is a milestone birthday in anyone's life, as it marks the start of the teenage years and growing into a young adult. Celebrate your son's special day by planning a day of all his favorites, including his favorite foods, birthday cake and a fun activity of his choice -- whether it be a big, elaborate party with all his friends or a simple dinner at home with the family.

Start planning your son's 13th birthday party a few months in advance, especially if you are renting a location venue, hiring caterers or have a large guest list, to ensure that you are not rushed and have time to prepare all the details and purchase supplies.

Ask your son to choose a theme or color choice for his birthday party, so you can purchase decorations, cups, plates and napkins. Avoid "childish" themes; teenagers can be self-conscious and want to feel more grown up, so let them choose how their party is set up, especially if they are having friends over.

Create a guest list and decide what type of party to have -- a family gathering, a mixed party with friends and family or a get-together with just him and a group of his friends. If the guest list includes both boys and girls, go over rules of conduct with your son before the party, and/or assign an adult chaperone to supervise or check in on the teenagers. Once the guest list is created, hand out or mail invitations a couple of weeks before his birthday and specify an RSVP date, so you will have an accurate head count when you get food and drinks for the party.

Select a location for the birthday party -- your home, a park, a local pool, the beach or a bowling alley -- to celebrate your son's big day. If the party is located outside your home, be sure to call at least a month ahead of time and make reservations, to ensure you get the space and date you want.

Arrange a fun activity for your son and a few of his closest friends during the morning before his birthday party. Ask your son what he would like to do, or surprise him and treat him to a movie, a game of bowling, laser tag, go-kart rides or an elaborate visit to a theme park. If your son prefers a more low-key start to his big day, then let him relax, play video games or do another activity of his choice.

Provide food, drinks and other refreshments for the party by hiring a caterer and ordering prepared foods -- sandwich trays from a grocery store deli or take-out from your son's favorite restaurant -- or making some of his favorite homemade dishes. Teens might also enjoy a buffet-style spread with their favorite finger foods, such as mini-burgers, nachos, wings and assorted chips and dips. Serve a variety of drink options, including water, fruit juices and soda. Make a homemade cake or take your son to a bakery, and let him choose a custom cake. Don't forget the ice cream!