Implement sessions in your training where you do your kicks slowly, extremely slowly. It helps to get aware of and develop correct technique which will help you with your balance. And as Squirrelfighter said, the specific muscles and also the neuronal connections have to be developed as it's a body motion you're not yet used to. That takes some time.
Another way to improve your balance is to stand on one leg as often as you can. There is plenty of "dead" time in your day where you can do it without losing time: right in morning, while taking your breakfast out of the fridge, in the bathroom while brushing your teeth, under the shower, while waiting for the bus, in the elevator to your office (if you don't use the stairs for a little cardio workout) etc.