You can choose to do exams and follow a specific program going through the grades, or you can choose a more avant garde approach that suits your personal desires more. I have had students take instruction from me so that they can best accompany their church band by learning how to play chords in different ways. Many adults have yearned for their own arrangements to match their singing style and we have ways to do that in accordance with their skill level.
Music composition is made easy through the use of a piano in collaboration with a music program on a computer so that you can hear the completed work as it progresses.
Children with little hands and lack of control can start playing piano while learning about rhythm. I teach little ones through various games, using colour and animal cards etc, so that they are fully immersed in the music experience.