Date Comparison in iOS

Date Comparison in iOS

I'm trying to check if the time between two dates is larger than 3 months,
but have had no success. Here is what I am trying. Am I doing something
incorrectly? Even if I set the detailTextDate at yesterday, it will still
display the evaluationLabel. Do I need to set a dateFormat?
NSString *detailTextDate = @"August 11, 2013";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
dateFormatter.dateStyle = NSDateFormatterLongStyle;
NSDate *startDate = [dateFormatter dateFromString:detailTextDate];
[dateFormatter setDateFormat:@"yyyy-MM-dd hh:mm:ss"];
NSDate *todaysDate = [NSDate date];
NSCalendar *gregorianCalendar = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
NSDateComponents *components = [gregorianCalendar
components:NSMonthCalendarUnit
fromDate:startDate
toDate:todaysDate
options:0];
if(components.month >= 3){
evaluationLabel.hidden = NO;
}
}
//tried using NSYearCalendarUnit, Month, Day etc.
//startDate = 2013-08-11 06:00:00 +0000, detailTextDate = August 11, 2013,
components = //<NSDateComponents: 0x176c3c70>
// Month: 0