c# - Object reference not set to an instance of an object, generating win forms control via code

I'm making a simple space invaders type game for my class and I'm trying to generate everything through my code. I have 3 methods causing me a problem

private void Form1_KeyDown(object sender, KeyEventArgs e)
{
    if (e.KeyCode == Keys.Space)
        GenerateBullet();
}
private void GenerateBullet()
{
    playerBullet = new PictureBox()
    {
        Parent = backBoard,

        Size = new Size(4, 12),
        Visible = true,
        Enabled = true,
        Image = Properties.Resources.Untitled,
        SizeMode = PictureBoxSizeMode.StretchImage
    };
}
private void BulletMovement(object sender, EventArgs e)
{
   if (playerBullet.Enabled == true)

   {
       playerBullet.Top += 4;
   }
}

The 3rd method that checks the enabled and moves based on that is what is throwing the error 'Object reference not set to an instance of an object.' . Is there a way to fix this without actually generating the picture through the toolbox/form design.

The BulletMovement is called by a timer tick sorry that I didn’t make that clear