Hi there  mustachioedcat!
It sounds like you and your sister are using the same Apple ID account for Apple Music. We'll be glad to help you remedy this issue.
To avoid sharing a profile, you each would need to create and use your own Apple ID to use for Apple Music, iTunes, the App Store, iCloud etc. if you haven't already.
"Family Sharing requires a personal Apple ID signed in to iCloud. If your family has purchase sharing turned on, apps, music, movies, TV shows, and books can be downloaded on up to 10 devices per account, five of which can be computers." Find out more about this here: What is Family Sharing?
If you don't have your own Apple ID created and are unsure on how to create your own Apple ID, look here: How to create a new Apple ID
Once you have created your Apple ID and signed into Apple Music by going to under Settings > tap name > Media & Purchases. Then, go to the Music app and tap the profile picture on the top right hand-side.
If your profile isn't showing, scroll to the bottom and tap Show Apple ID. If the Apple ID is incorrect, sign out and sign in with the correct credentials.
You should be able to make your own playlists now and no longer see each other's music. Get an Apple Music family subscription
We hope this helps.
Enjoy your weekend!
