How to find days remaining in birthdate

I want to find the remaining days from array of birthdates. I'm using following code for it

for(int i =0;i<_convertedBdates.count;i++){
         
    NSDateFormatter *tempFormatter = [[NSDateFormatter alloc]init];
    [tempFormatter setDateFormat:@"dd/MM/YYYY"];
    NSDate *firstdate = [tempFormatter dateFromString:[_convertedBdates objectAtIndex:i]];
     
   
    NSString *curYear = [tempFormatter stringFromDate:[NSDate date]];
    NSDate *secondDate = [tempFormatter dateFromString:curYear];
    NSTimeInterval lastDiff = [firstdate timeIntervalSinceNow];
    NSTimeInterval todaysDiff = [secondDate timeIntervalSinceNow];
    NSTimeInterval dateDiff = lastDiff  - todaysDiff;
    int day = dateDiff/(3600*24);

    NSLog(@" _newlymadeArray %@",[_convertedBdates objectAtIndex:i]);

    NSLog(@" days %d",day);
    [_daysremaining addObject:[NSString stringWithFormat:@"%d",day] ];
    }
    NSLog(@" days %@",_daysremaining);

What am I doing wrong, why am I not getting correct days?

for(int i =0;i<_convertedBdates.count;i++){
    NSDateFormatter *tempFormatter = [[NSDateFormatter alloc]init];
    [tempFormatter setDateFormat:@"dd/MM/YYYY"];
    NSDate *firstdate = [tempFormatter dateFromString:[_convertedBdates objectAtIndex:i]];

    NSString *curYear = [tempFormatter stringFromDate:[NSDate date]];
    NSDate *secondDate = [tempFormatter dateFromString:curYear];
    NSTimeInterval lastDiff = [firstdate timeIntervalSinceNow];
    NSTimeInterval todaysDiff = [secondDate timeIntervalSinceNow];
    NSTimeInterval dateDiff = lastDiff  - todaysDiff;
    int day = dateDiff/(3600*24);
    day = day -1;
    NSLog(@" _newlymadeArray %@",[_convertedBdates objectAtIndex:i]);

    NSLog(@" days %d",day);
    [_daysremaining addObject:[NSString stringWithFormat:@"%d",day] ];
}
NSLog(@" days %@",_daysremaining);