NSDate few year ago from today. NSDate to future or past date.

    

    NSDate *today = [NSDate date];

    NSLog(@"today: %@", today);

    NSCalendar *gregorianCalendar = [[NSCalendar alloc] initWithCalendarIdentifier:NSGregorianCalendar];

    NSDateComponents *offsetComponents = [[NSDateComponents alloc] init];

    [offsetComponents setYear:-18]; // setting it to -18 (near 18 years ago,from today, +18 will shift to future date)

//    [offsetComponents setMonth:-1];

//    [offsetComponents setDay:-1];

    

    NSDate *newShiftedDate = [gregorianCalendar dateByAddingComponents: offsetComponents toDate: today options:0];

    NSLog(@"newShiftedDate: %@", newShiftedDate);