Issues with non-greek mothers
 

My mom wasn't in a sorority, she went to school in Finland where they don't have sororities. My mom and I are very close and usually I tell her everything. We had initiation last night (yay!) and I'm not going to tell my mom anything but I can tell that she's very hurt that I can't/will not tell her what happened last night. I told her everything I could about my night before and after initiation but I can tell she's upset she doesn't get to know. How have people dealt with this in their own lives?

My mom was sorta like this at first too. She didn't go to college and doesn't really understand why it is secret. However, she'll come around to understanding how important it is to you and why you do not want her to know.

It should be more than fine to just say the basics: there was a ceremony with your sisters, you learned some deeper history/meanings about the sorority, you really enjoyed it, etc. Stuff like that is pretty universal among sororities, but most moms should find that level of explanation satisfactory. If she is seriously bugging you to tell her specific ritual/secrets, then I'd be extremely surprised.

Sorry to crash your forum...
You could also talk about how the ceremony made you feel without going into specifics. If it's not private, maybe tell her where the ritual was and what you wore, how you traveled to initiation. Talk to her about your new pin. Did you all have a reception afterwards you could talk to her about?