date of birth validation

Question

i have one field in design page as follows;
 
Date of Birth textbox1(calendar image)
 
i want to validate date of birth date should be greater than the todays date and more than the todays date.
 
for that i write the code as follows;
 
DateTime DOB = Convert.ToDateTime(FromDate.ToString());
 
if(FromDate.SelectedDateValue > DateTime.Now)
{
Label6.Text = ("you have not born yet");
} 

i try the above code when i run i show the error message as follows;
 
Operator '>' cannot be applied to operands of type 'string' and 'System.DateTime.
 

for my above code please correct my code and reply.

thanks,please help me.