I would wait until you have done your riding course as well, but if you are like me and can’t wait…I was told that if you must get one, get the bike with the most standard riding position since most people will have better control in this position…so if you sit more upright on the 250, that is probably the way to go. It will also be a lighter bike which will help you in the learning curve.
And as a Canadian, I would like to thank you for enlisting and serving your country, and really, the whole continent. I salute you. Good luck.