Wrong index of the checkbox column in datagrid

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checkbox

I have this code to add a checkbox to the 3rd column of the datagrid, but the index of this columns is 0 and not 3. Does anyone understand this error and how to fix it? Thanks

public void bloqselect()
       {
           DataGridViewCheckBoxColumn chkSelect = new DataGridViewCheckBoxColumn();
           chkSelect.Selected = false;
           chkSelect.HeaderText = "Bloqueador";
           chkSelect.Name = "chkSelect";
           grid_lic.Columns.Insert(3, chkSelect);

           if (chkSelect.Selected == true)

               bloqueador = 1;

           else
               bloqueador = 0;
       }