Exciting idea. Taking lessons should ideally be a decision coming from your child’s desire to do so.
Try first. If you are not sure whether your child is ready, try one or two lessons first. This will give you an idea, and ask your teacher for a feedback too.
What age to start. There is no definite answer to what age lessons should begin. It depends on your child’s learning development stage. Yes, your child can be five, however, from a learning development perspective, age six or seven is usually more suitable.
Realistic assessment. Before you look for a teacher, review your work, study or family commitment. Preparation between lessons is essential to learning. If you are already too busy, after a few lessons you will find yourself struggling with making a progress.
Good instrument. If you have an acoustic piano, make sure it’s tuned, at least once a year. If your space is limited, get a digital piano but make sure it has weighted keys.