WinForm c#: Check first run and show message

I am creating a winform application containing first run check. I've been following these 2 articles:

• How can I check if a program is running for the first time?


• Windows Forms User Settings in C#

First run check is supposed to check if application has ever been run and if not, it should show some message to the user. Problem i am having is, that this message is displayed before winform application is initialized/displayed and I am not able to find out why. Here is my code:

Program.cs

public static void Main()
{
    Application.EnableVisualStyles();
    Application.SetCompatibleTextRenderingDefault(false);
    Application.Run(new Form1());
}

Form1.cs

public Form1()
{
    this.InitializeComponent();
    CheckFirstRun();
}

private static void CheckFirstRun()
{
    if(Settings.Default.FirstRun)
    {
        MessageBox.Show(
            "First run");
        Settings.Default.FirstRun = false;
        Settings.Default.Save();
}

It shows Message box with msg: "First run" and after clicking OK button it shows WinForm. What I am trying to achieve is to Display WinForm first and if it is first run then show this msgBox.

Any ideas?