The fear of practicing martial arts at home and without formal training is that you can get injure or you could injure your body. But there is no such fear in a martial art center. Floor at the center is equipped for martial art training. For home practice, you need a Taekwondo mat.
Martial art training can be taken from online tutorials and DVDs but you can’t practice martial art exercises on hard and slippery floor of your home. It could be accidental to practicing jumping and kicking exercises on marble or tiled floor. But there is way to make your home floor safe for martial arts exercises and that is to practice exercises on a Taekwondo mat.