Please I need urgent help. Kindly advise:

So my wife has a qualification exams in Canada on August 11. She's in need of a visitor's visa to Canada for like a week for this exams. We checked yesterday and saw that the average processing timeline for a visitor's visa applied in Nigeria is 146 days while in Cameroon is 34 days. I was told this is because of the backlogs of untreated applications from Nigeria.

We have about 3 months to this exam and scared that should we decide to apply in Nigeria, the application may never be looked at before the exams date. We don't know if it is possible and a good idea to apply in Cameroon or another neighbouring country since the applications can be done online as well. My wife is about 8 months pregnant now and will be due anytime next month.

Please kindly advise for those who have had experience regarding this.