新手编程，求解，我运行不出结果，大家可帮我看看是不是哪里出错了？

public string stdBir;
这个是string 类型..改成dataTime类型

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
      public   static void Main(string[] args)
        {
            Student std1 = new Student();
            std1.stdno = "2013080452";
            std1.stdName = "张三";
            std1.stdSex = "男";
            std1.stdBir = new DateTime(1992, 1, 12);

            int age = std1.getAge();
            Console.WriteLine(age);

            Student std2 = new Student();
            std2.stdBir = new DateTime(1989, 5, 12);

            int age2 = std2.getAge();
            Console.WriteLine(age2);
            Console.ReadKey();
        }
    }
}

            public class Student
            {
                public string stdno;
                public string stdName;
                public string stdSex;
                public DateTime stdBir;

               public  int getAge()
                {
                    DateTime nowTime=DateTime.Now;
                    return nowTime.Year-stdBir.Year;
                }
            }

更新的新手表示学到了一点东西呢。。