Yes, you report all income and any ordinary, necessary expenses used to earn that income. Any money earned for services performed is considered business income and self-employment if not done for an employer or outside of your normal employment. In your case it's music lessons. The link provided will show details to help you complete your business income.
For your information I have provided information about business versus hobby income per the IRS.
This IRS link will guide you: Business or Hobby?
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