When I was younger I didn't realize why the counter drop was such a difficult shot; you're right at the front of the court, you have a short swing, it should be easy, right? Well you're also running near full speed, lunging and you also have to stay towards the middle of the court so you don't give up a stroke. Most kids aren't strong enough yet to lunge properly to play this shot which means they won't be able to put a proper swing path to play this shot.
You see it's very challenging to play a delicate shot when moving quickly, trying to stay balanced and also having to clear quickly. If you pop up the ball just a bit you are toast, if you can't clear towards the middle you are also in big trouble. Think about how often you practice your drives or volleys compared to your counter drops...if you're not very consistent with this shot it's likely because you haven't grooved this swing yet. If it's a technical problem have a peak at my video and see what I do. FYI - you don't need to try the deceptive drops if you can't hit a regular drop yet, but play around with both. Here it is: