Why is my sister getting all my photos on her phone.
My sister and I just recently both got iPhone 6 and we share an Apple ID, how come we are getting all of each other’s picture?
Were you syncing photos with iCloud Photo Library on the old phones? If you continue to share an Apple ID, you will get/see each others data. You might consider creating a new Apple ID for one of you so you will have different Apple IDs. You can ask your parents if they will set up Family Sharing so you can continue to share apps.
There may be some data loss, but you can minimize it. If syncing photos with iCloud, ensure Optimization is turned off in Settings/Your Name/iCloud/Photos and/or in Photos/Preferences/iCloud. Then make sure full resolution photos are on the device/computer. When signing out of iCloud, if asked whether you want to retain data, choose yes. Messages conversations will be lost if they are addressed to the ID. See the article below for other places that the old ID should be removed. Also set up Family Sharing to keep access to your apps. Also see Winston Churchill's response in the below discussion
How to transfer all files from one iCloud account to another
Apple ID email address or password - What to do after you change
Family Sharing - Use your own Apple ID for Family Sharing
Family Sharing -What types of content can I share?
Family Sharing - If you don‘t see your family‘s shared content
Family Sharing - purchases and payments
Family Sharing - Hide and unhide music, movies, TV shows, audiobooks, and books
Family Sharing – share iCloud Storage
Family Sharing - Share an iCloud storage plan with your family
