Fleeting reassurance

1. My own personal copy of Griffiths and Harris has arrived! This makes me happy.
   
2. My graduation photographs have arrived. I look like I can't spell the word mathamatics (sic), let alone do it...
   
3. I got an email from my Germany supervisor. The email began Dear Ms. *my surname*/*my first name* and ended Prof. *his surname* /*his first name*. I am confused. I ideally would rather he called me by my first name, but I would never dare call him my his first name. I am generally confused by the student/supervisor etiquette? I really really don't want to be unwittingly rude. Hopefully there aren't too many pitfalls here... but I can't be sure... Regardless, I am very excited about this. I absolutely can not wait to talk to him about what I am doing. Earlier I was having doubts about choosing Germany; I was wondering if my Canada option might have been a better choice for me- but now I feel somewhat reassured.