As was recently discussed on a smilar subject the standard depends so much on which area you are in.
I would say it is never too late but I would have thought that your child should be working on papers at the level of the real exam by now.
Perhaps you should let her try & then work together through the areas she finds difficult.
Don't worry too much if she isn't working to time yet - virtually all children will speed up with practice.
I would say that you will need to keep going through the summer holiday though.
Sure you will get lots more opinions
Might be worth trying the forum for your area for advice on standard your daughter needs to be working at to be in with a shot.
Hope it goes well.