It has already been mentioned.
Nothing wrong with your brakes.
Most bikes now have two big discs and calipers on the front and one small disc / caliper on the rear.
There is far too much braking power available to control a bike with the front brake at slow speed.
You will find using the front brake at slow speed say approaching a junction, that the front tends to bite a little too much, the front end dives a little, and steering becomes heavy.
If you use rear brake for slow speed, you drag the rear end. This make s the rear squat a little, bike doesn't nose dive and steering is easier. simply because there are now no forces in the front end.
when out on the open road and you want to lose some speed Front brake (then a little rear) and when down to 20mph and below rear brake.
Another good tip, when you approach junctions (give way etc) point the bike in the direction you want to go if it is safe to do so. This allows you to pull away on a straighter line (excelerate quicker) and avoid those horrible sharp corners.
Hope this helps.