Apple ID Sharing with daughter My daughter and I both have apple phones and up until about 1 month ago she was always logged in on her device using my apple id.  

I am trying to find out does this give her access to make any changes on my phone (not necessarily on purpose or even knowingly).  Specifically, under contacts, where my name is listed, right under my last name was listed a nick name that I didn't put there.

Could she have some how on her phone updated my either her name and it transferred over to my name because of the sharing issue?  Or if she was talking to Siri and she asked Siri to call her something, could that have updated to both her name and to mine?  

I'm trying to figure out how it got there when I didn't put it there, or how to avoid that problem in the future.
To prevent future problems, disable the current set up (where you have second device under Apple ID, but it is actually your daughter).

Just change the password on your Apple ID so she can not log in to that.

Then set her up as Family sharing, where you have some control over her account.

Follow Apple Instructions on how to.