She should do great. Your biggest challenge is to get her more relaxed and 'slow footed'. Cutters, especially trained cutters, are naturally quick footed and have to be taught to move easier and slower. I liked training them because they are so responsive and sensitive.
I do not know if you are looking at local showing or big AQHA Shows. I have seen a real prejudice at the big shows against horses that do not have 'the look' of the pleasure and rail horse horses. You know, the 16.2 hand horses that are about 6 inches wide and show in false tails that drag the ground and get tangled around their hocks. You will also have to decide if you want to keep her nice long cutter/reiner mane or pull it, thin it and shorten it to a short banded mane.
Have you thought about learning how to rein and do working cowhorse on her? I'll bet she would be great there and it would be more within her 'type' and natural ability.