I was in early December class. Nobody got ORD out of training, but most people who wanted it got it about a month after LOE. It entirely depends month to month though, but everyone from my class who wanted ORD or MSP got it within a month. In fact, everyone got their base of choice within a month, except for those who wanted SEA who are all still waiting since February. That being said, it is SkyWEST. Don't be surprised if you end up with a western base at least at first. High chance of being thrown in SFO.