using System;

using System.Text.Json;

public class Program

{

    public static void Main()

    {

        Console.WriteLine(Test.Age);

        Console.WriteLine(Test.Age);

        Console.WriteLine(Test.Age1);

        Console.WriteLine(Test.Age1);

    }

}

​

public static class Test

{

    private static Guid GetId()

    {

        Console.WriteLine("Created");

        return Guid.NewGuid();

    }

    public static Guid Age {get;} = GetId();

    public static Guid Age1 => GetId();

}