calender extender query - displaying result in textbox ??

hi,

I am using calender  extender in a form that is completed by USers

The problem is the selected date is displayed in the TextBox  like so

3/21/2017

This is ok for US users but I have English users and to them its the wrong format.

to solve the problem I want to display the date like this so everybody understands...

21 March 2017

here is my code

<asp:TextBox ID="txtDate" class="form-control" placeholder="click here to see calender" runat="server"></asp:TextBox><br /><asp:RequiredFieldValidator ID="RequiredFieldValidatorDate" CssClass="alert-text" runat="server" Text="Select Date"  ForeColor="Red"
                ControlToValidate="txtDate" ErrorMessage="Select Performance date" ToolTip="date  is required."
                                          SetFocusOnError="True" Display="Dynamic"></asp:RequiredFieldValidator><asp:CalendarExtender ID="DateTextBox1" TargetControlID="txtDate" runat="server" />

thank you