is it too late to do this?

It depends when your exam is - flashcards are good when used over a fairly long period of time and used consistently. At this stage, it’s best to be refining technique for exam questions and looking over past papers to get an idea at the sort of questions they might ask you and the structure they use, as well as any tips your teacher gives you.

i have 1 week until the gsces exams are going to happen