If you're in a Family Sharing group, and you change to a Student Membership, your family organizer will be billed for both your Student Membership and the Family Membership to Apple Music. If you're the organizer of a Family Sharing group, and you change to a Student Membership, the rest of your group will lose access to Apple Music. The next time they sign in to Apple Music, each family member will see an option to join as an individual member.