If you didn't reply when you got the email last Friday then it probably wouldn't hurt to go on and reply now. Something along the lines of thanking her for the update and that you're looking forward to talking with her again soon would be appropriate without being appearing pushy.
If you did already reply, it may be best to wait it out. Real life can sometimes interfere with sorority plans. Hopefully you'll hear back from her sooner rather than later. Waiting is hard, but very important in the AI process.
Patience is always a virtue
, no matter how hard it is! Good luck.