You need to check visa bulletin website for current priority date. For your spouse it will be catagory F2A, so check the priority date. Now it may be showing nov 15, 2015. It means the priority date is current for the people who filed in november 2015 and their document will get process now. Lets say u file it now your priority date will be oct 2017 and ur spouse's document will process when that date gets current on the website. Keep in mind those dates may change rapidly or slowly and depends on country quota too. People tends to be get citizenship in 4.5 yrs and bring their spouse in that case takes around 2months not much questioning. I agree with dhoti_prasad, other means of gc might get question more. And lawyer's help is always good. Hope this helps.