If my sister use my ID, can she look at my photos, messages, apps in her new iPhones?

If you have synced data to iCloud, including photos, she will be able to see the data. She can log in and see your messages. She can look at your purchases history to see what apps you have downloaded. She can't directly access your phone.

If you want to be generous in this way, don't simply give your password to your sister. Instead, you handle her phone and download the items you have agreed to provide her. In this way, she won't be able to go into your ID again in the future without your knowledge.