Need of input validations in class

using System;

namespace AboutClasses

{

    class P2ClassWithOutValidations

    {

        //Business rule 1: name should not empty

        //Business rule 2: age should be from 18 to 60

        class Person

        {

            //instance variables

            string name;

            int age;

            //instance methods

            public Person(string name, int age) //constructor

            {

                this.name = name;

                this.age = age;

            }

            public void disDetails()            //normal method

            {

                Console.WriteLine("Name {0}",name);

                Console.WriteLine("Age  {0}",age);

            }

        }

        static void Main(string[] x)

        {

            //null value to name,

            Person p1 = new Person("",20);  //Rule1 Violated

            p1.disDetails();

            //Age out of valid range

            Person p2 = new Person("Kumar", 10); //Rule2 Violated

            p2.disDetails();

            Console.ReadKey();

        }

    }

}

Output

Name 
Age  20

Name Kumar
Age  10

Note: 
1. The first output displays the empty value in the name field.
2. The second output displays the age of less than 18.

the Same program can be rewritten like below with validation methods.

using System;

namespace AboutClasses

{

    class P2ClassWithValidations

    {

        class Person

        {

            //static methods         

            static public bool ValidateName(string name)

            {

                if (name.Equals(string.Empty))

                {

                    Console.WriteLine("Name can't be empty");

                    return false;

                }

                return true;

            }

            static public bool ValidateAge(int age)

            {

                if (age < 18 || age > 60)

                {

                    Console.WriteLine("Age out of range...");

                    return false;

                }

                return true;

            }

            //instance variables

            string name;

            int age;

            //instance methods

            public Person(string name, int age) //constructor

            {

                this.name = name;

                this.age = age;

            }

            public void disDetails()            //normal method

            {

                Console.WriteLine("Name {0}",name);

                Console.WriteLine("Age  {0}",age);

            }

        }

        static void Main(string[] x)

        {

            ReadInputs:

            Console.WriteLine("Enter candidate name");

            string nm = Console.ReadLine();

            Console.WriteLine("Enter candidate age");

            int age = int.Parse(Console.ReadLine());

            if (Person.ValidateName(nm) && Person.ValidateAge(age))

            {

                Person p = new Person(nm, age);

                p.disDetails();

            }

            else

            {

                goto ReadInputs;

            }

            Console.ReadKey();

        }

    }

}

Output

Enter candidate name

kumar

Enter candidate age

2

Age out of range...

Enter candidate name

Rajesh

Enter candidate age

15

Age out of range...

Enter candidate name

Chitra

Enter candidate age

20

Name Chitra

Age  20