(5/6 years at the youngest)
A full size keyboard is essential, preferably an Acoustic Piano or a Digital Piano.
Even with tiny hands, full size, weighted keys will make all the difference to how quickly  progress is made.

However, a full size touch sensitive keyboard is adequate to begin with. (Touch sensitivity means when a key is played firmly, the volume will be louder than when a key is more gently played)

Even the youngest student is encouraged to:-
*Practise 5 times a week
*Prepare for relaxed, fun concerts
*Make recordings
*Compose their own music
*To have fun!