you can but first you might want to get her to RUN a lot,i have a six pack,well more or so because i did ballet,and i run a lot,its natural and then when i do exercise my abdominal muscles it just defines more,get her to eat protein and that you know the deal.work all of them not just one core part,and do more reps? and rest the next day. It kind of depends on your build,you can slightly see mine,but my stomachs naturally flat because i'm thin but make sure she runs first,for a few days and tones up her WHOLE body and then starts doing it after like two weeks of extreme healthy eating and exercise,cardio is the best any form of it really.
Practice and drive are all you need, You will become good, if not great, and then, if you wish to go further, the opportunities will come to you - Rome_Leader