All school textbooks I Am Studying Clarinet are mainly composed of technical exercises, ie. etudes.
In addition to scales, etudes are most important for the development of future instrumentalists. By playing etudes you succeed in:
If you practice hard every day one day you will be able to play the hardest clarinet piecese.
Etudes in this textbooks (I Am Studying Clarinet I-IV) are suitable for your age and its needs. They were chosen carefully so as not to be monotonous, but melodic and appealing – like small pieces.
If you take seriously their importance, I am convinced that you will be pleased to practice them.
Taken from my book
I Am Studying Clarinet II