Basic PersonModel Program

using System;
using System.Collections.Generic;

namespace testProgram
{
    public class Program
    {
        public static void Main()
        {
            PersonModel jason = new PersonModel("Jason", "Young", 33);
            PersonModel joe = new PersonModel("Joe", "Smith", 44);
            PersonModel mark = new PersonModel("Mark", "Jones", 26);

            List<PersonModel> people = new List<PersonModel>();
            people.Add(jason);
            people.Add(joe);
            people.Add(mark);

            foreach(var person in people)
                person.DisplayPersonInfo();
        }
    }

    class PersonModel
    {
        private int Id {get; set;}
        public string FirstName {get; set;}
        public string LastName {get; set;}
        public int Age {get; set;}

        public PersonModel() {}

        public PersonModel (string firstName, string lastName, int age)
        {
            this.Id = GetId();
            this.FirstName = firstName;
            this.LastName = lastName;
            this.Age = age;
        }

        private static int personId = 1000;

        // Set unique Id for each created person
        private int GetId()
        {
            return ++personId;
        }

        public void DisplayPersonInfo()
        {
            Console.WriteLine("ID: {0}  First Name: {1}, Last Name: {2}, Age: {3}", this.Id, this.FirstName, this.LastName, this.Age);
        }

    }

}