I think no, she does not have to, she can go SS office for SS change and start working I am not expert on it, just a logical guess, by the way how long did it take to get EAD after finger print one of our user @ny2 knows better if he gets chance to click this thread

There is no straight answer. I just went through the same process. But we were suggested to register for classes until the case was approved. But we just registered for 1 class as a safe bet.

@thukka It took approximately around 60-70 days after the fingerprint.