Maybe she is not lazy at all. Maybe she just doesn't want to work on things that don't motivate or interest her. It is my ultimate goal to never have to work on things that don't interest me if only I can figure out a way to automate all of that ;)
The fact that she has succeeded in getting A's with waiting until the last minute and not putting in much effort, indicates that she is very smart. I have noticed that really smart people seem to lack motivation and get bored very easily. The two closest people to me are like this. The thing is though, when they find something that does interest them, there is no stopping them. They turn into the hardest working people around.