But Jamaica is not visa exempt. So does Canada allow those with student visas from the US or UK (even if not from a visa exempt country) to enter without a visa for Canada?
In answer to Alicia's question about inland vs. outland, I would recommend outland. You already know that the marriage is going to be closely examined because of age difference. So it's doubtful you would receive Approval In Principle at the 2nd stage of the INLAND processing and would be interviewed locally. You also must remain in Canada during the total processing of your application (or it is at least highly recommended). The total time it is likely to take on your file could be well over a year, maybe closer to 2 years. And, if you are refused, you have no right of appeal for an inland application. The only rememdy available to you then would be judicial review where you must prove an error in law to have the application reassessed.
For an OUTLAND application, you can still be living in Canada with your spouse (as it seems you are?) while the processing is ongoing assuming you maintain legal status here. Sponsorship approval (first stage) takes about 45 days and then the file is sent to the embassy in Kingston where it is processed. I'm not sure about their processing time but I think it's around 9 months or so. Now you may be requested to appear for an interview which is also likely because of the age difference. You must be prepared to travel to Jamaica to attend this interview. Even given all of that it is likely that the processing will be faster with an outland application. However, another big benefit to this route is that if you are refused, you have the right of appeal to the Immigration Appeal Division of the Immigration Refugee Board. This is a MUCH better route than judicial review as the IAD will allow new evidence and you WILL be heard whereas getting leave to appeal to the federal court is ify at best.
Whatever you choose, make sure you are prepared, organized and maintain your legal status here in Canada. You also might want to consider hiring a GOOD consultant or lawyer to assist you. Good luck.