I hate to say this...but if she is in the middle of revision...and I am assuming this may be for University...then she is most likely immersed in a stack as tall as you of books,notebooks,loose notes everywhere.empty coke bottles,stale pizza, the considerable bits and bobs of her child, toys...etc.
Now-rereading this thread..I see that she is a mature lady......so it may not be as bad as the above. But if she is juggling so many things...does she also work?....then SOMETHING has to go on the back burner. It doesn't mean she is not interested...but she has HAD to set priorities,and a full-on relationship would have been way too much of a distraction. Let her get past her exams,then see if things develope into something more closely resembling a real relationship.....THEN you can make more of a judgement about how things are progresing.