Problem with get set value user control

[Nemo]

I have problem to get my dates from my user control.

The problems is that the datetimes sets after when I get the values
from my aspx page.

Here is how my user control lock likes.

private void Page_Load(object sender, System.EventArgs e)
{
if (!IsPostBack)
{
// set startDate and endDate
StartDate = new DateTime(1990,04,04);
EndDate = new DateTime(1993,04,05);
}
}
private DateTime startDate = new DateTime(1900,01,01);
private DateTime endDate = DateTime.Now;

public DateTime StartDate
{
get
{
return startDate;
}
set
{
startDate = value;
}
}

public DateTime EndDate
{
get
{
return endDate;
}
set
{
endDate = value;
}
}
}

And this is my aspx file
private void Page_Load(object sender, System.EventArgs e)
{

datediff myDateDiff= (datediff)LoadControl("datediff.ascx");
phDateDiff.Controls.Add(myDateDiff);
DateTime startDateTime = myDateDiff.StartDate;
DateTime endDateTime = myDateDiff.EndDate;
}