Agree w everything jomz said, and yes if an interview is required, which might be likely in your case, expect much longer processing times, and even longer if you get a refusal and appeal
To show that age difference can be a problem sometimes, look at this most recent thread. Case is almost sinilar to yours: age difference with younger spouse being Muslim male
http://www.canadavisa.com/canada-immigration-discussion-board/pr-visa-denied-t409672.0.html
By the way, in that thread I asked if her husband was the younger one or her, but even before she answered me, I already knew it was likely the husband was younger.