I would lean towards it wasting your time Cabingirl. You're going to be learning an exceedingly large amount of information while you're at GS, so it is best not to fill your brain with irrelevant things they don't give you. My best advice to you for your last few weeks until it starts is just to take care of yourself, get plenty of rest and enjoy the calm before the storm (because when training commences sleep might be scarce!).