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

    public People(int age, string firstName, string lastName)
    {
        Age = age;
        FirstName = firstName;
        LastName = lastName;
    }

    public void Present()
    {
        Console.WriteLine($"Hello, my name is {FirstName} {LastName}. I'm {Age} years old.");
    }
}

People Me  = new People(21, "Corentin", "Nelhomme");
Me.Present();