for (int i = 0; i <= txtIteration.Value; i++)
{
   Age1 = (((CurrentDate.Year - StartDate.Year) * 365 - 
                 StartDate.Month * 30 - StartDate.Day + 
                 CurrentDate.Month * 30 + CurrentDate.Day) / 365);
                CurrentDate = CurrentDate.AddDays(1);
}