why is my daughter receiving my text messages on her phone at the same time I received them?

To fix this go to Settings>Messages>Send & Receive and do one of the following:

1. Either uncheck the email address shown under "You can be reached by iMessage at" on both phones; or
2. If you want to continue to receive iMessages at this email address, on one of the phones, tap the Apple ID at the top, sign out, then sign back in using a different Apple ID (so both phones are using a different Apple ID for iMessage). Note: you can continue to share an Apple ID for purchasing from the iTunes and App stores. It does not need to be the same as the ID you are using for iMessage, FaceTime and other services.