Calculate age based on birthday

using System;

public class Program
{
    public static void Main()
    {
        //get todays date and the birthdate
        DateTime today = DateTime.Today;
        DateTime birthday = new DateTime(1987,1,23);

        //calc difference in years
        int age = today.Year - birthday.Year;

        //Check to see if birthday has happened yet. If not adjust age down by 1
        if (birthday.DayOfYear > today.DayOfYear)
            age = age -1;

        //Display age on Console
        Console.WriteLine("Your current age is {0}.", age);
    }
}