This is a valid thing to bring up, but remember the conversation they had in the astral dimension? She left her body and although she wasn't exactly happy about it, she technically did accept her death and admitted that life is beautiful because it is limited. If she truly didn't want to die in that moment, you'd think she would have asked Strange in that conversation to use the time gem and reverse the incident. Because of this, I don't think he would have used it without her permission.
kill ur self Chris I know this dude the bitch is bad