My thought is that if she was stuck in a bad traffic situation or other good reason, that she could have just been honestly late. I'd see what happens next session. I never answer my phone when I'm driving for safety reasons, and if she was stressed about driving AND lateness, she could have wanted to spare you her stressed tone over the phone.

Ask her for clarification about the aunt comments. I once misunderstood my T's point about a similar comment and when I asked, his explanation really helped.

I'd give her a second chance and then decide.