Convert System.String generically to any complex type using “Convert.ChangeType()”

I try to generically convert user input into either simple or complex types:

class Program
{
  static void Main(string[] args)
  {
    Console.WriteLine("Welcome, please provide the following info... Confirm with <RETURN>!");
    Console.WriteLine();    

    Console.Write("Name (e.g. 'Peggy Sue'): ");
    var user = GetUserInput<User>(Console.ReadLine());

    Console.WriteLine();
    Console.WriteLine();
    Console.WriteLine("Hi {0}, nice to meet you!", user.Forename);
    Console.WriteLine();

    Console.Write("Age: ");
    user.Age = GetUserInput<ushort>(Console.ReadLine());

    Console.WriteLine();
    Console.WriteLine("Thanks and goodbye!");
    Console.WriteLine("Press <RETURN> to quit...");
    Console.ReadLine();
  }

  static T GetUserInput<T>(string data)
  {
    return (T) Convert.ChangeType(data, typeof (T));
  }
}

class User
{
  public User(string name)
  {
    var splitted = name.Split(' ');
    Forename = splitted[0];
    Lastname = splitted[1];
  }

  public static implicit operator User (string value)
  {
    return new User(value);
  }

  public static explicit operator string (User value)
  {
    return string.Concat(value.Forename, " ", value.Lastname);
  }

  public string Forename { get; private set; }
  public string Lastname { get; private set; }

  public ushort Age { get; set; }
}

For the conversion to my "User" class, I always get the exception "Invalid cast from 'System.String' to 'ConsoleApplication1.User'.". Does anyone know how to fix this?

If I try something like this (not generically), it works just perfect:

Console.WriteLine((string) ((User) "Peggy Sue"));