Mvc4 Date validation format not working dd/MM/yyyy with Bootstrap datepicker

Question

Hell, I want to add manually date in Text box with date format dd/MM/yyyy.. I have declared model validation, but i have found that MVc will not take part for Date validation, need to do with jquery, I have done like that but. here my some cases not wokring for example if i am entering 10/12/20 then i need to show the message dateformat is wrong as i want 10/12/2013. I am using also Bootstrap date picker..but it is hard to select old date using boostratp datepicker.. so i need to add manually date with Date Format validation.

//Model

[Required(ErrorMessage = "Birth Date is required")]
//[Display(Name = "When where you born?")]
[Display(Name = "Birth Date")]
[DisplayFormat(DataFormatString = "{0:dd/MM/yyyy}", ApplyFormatInEditMode = true)]
[DataType(DataType.Date)]
public DateTime? BirthDate { get; set; }

Below is Jquery

//Jquery
var dateFormat = "dd/mm/yy";
$("#BirthDate").datepicker({
    dateFormat: dateFormat,
    autoclose: true,
    orientation: 'top left'
})
.on('changeDate', function (ev) {
    var dob = new Date($("#BirthDate").val());
    var today = new Date();

    var Age = parseInt(today.getFullYear()) - parseInt(dob.getFullYear());

    $("#EighteenAge").val('');
    $("#EighteenAge").val(Age);


});

$(function ($)
{
    $('#BirthDate').on("keypress", function (e)
    {
        ValidDate();
    });

});

function ValidDate()
{
    $.validator.addMethod('date',
    function (value, element)
    {

        if (this.optional(element))
        {
            return true;
        }

        var ok = true;
        try
        {
            $.datepicker.parseDate(dateFormat, value);
        }
        catch (err)
        {
            ok = false;
        }
        return ok;
    });
}

please help some