I'm tired, so I admit my brain might be missing something, but I feel like my answer, 'She grew red' should also be accepted. I'm pretty sure I've read that places. As I said, tired, because I admit 'blushed' is a more elegant and succinct version and I just didn't think of it. But I feel like my answer should still be acceptable, shouldn't it?
The main thing is that you understand the German. Quibbling over the English translation is not really important. When you can speak German fluently you will not be translating everything into English first (unless you are working as a translator I suppose) so it won't matter.
But to answer your question, that would be a correct literal translation since "to grow" is a correct translation of werden and "grew red" is also an expression that could be used in English although not nearly as often as "she blushed" or "she went red".