My girlfriend has ADHD and has is usually procrastinating studying (she has a big exam in a few months), is there anything I can do to help her with this without being prying?

Break up now. She'll blame you for everything that goes wrong between now and a few months. Also, you dont want to be the guy driving her to every drug store in. 50 mile radius looking for Vyvanse and Adderall on finals week.