your element is what you feel a connection to, its a particular element that you find it easier to control and work with. In my opinion your zodiac sign has nothing to do with your element for example my element is air but im a leo which is a fire orientated zodiac.
Try to manipulate all elements, some you will be able to control others you may not but dont expect anything instantaniously it may take time depending on your natural ability to control energy. Remember practise as much as you can if it helps visualise when trying to make energy balls.
I hope this helps blessed be )0(