You can delete top 6 rows from datatable before binding it to GridView:
cmd.CommandText = "SELECT * FROM [" + getExcelSheetName + "]";
dAdapter.SelectCommand = cmd;
dAdapter.Fill(dtExcelRecords);
con.Close();
for(int i = 0; i< = 5; i++)
{
dtExcelRecords.Rows[0].Delete();
}
GridView1.DataSource = dtExcelRecords;
GridView1.DataBind();