Having a traditional ceremony is a good thing, however I do see at least one red flag you have, and that is you guys seemed to have gotten married very quickly (after knowing each other 4 mths) and on the first visit. That, among other things, might have caused you guys to get an interview request.
Also, these are considered red flags as well, which may or may not apply to you. Some of these red flags I've discovered based on cases I've read online:
-large educational/cultural/age difference
-either your or your wife's parents/family not attending the wedding
-unable to communicate in a common language, or using mostly a translator or translation software to communicate
-applicant has relatives living in Canada, or has married foreigners before
-applicant goes on dating site for example, doesn't know English, but writes her profile in English and indicates that she's seeking foreigners to date or marry
-one person is married before, the other never been married
-applicant has attempted to enter Canada before through a student visa or visitor visa, or has attempted to immigrate to Canada in the past
Best thing to do now is to order the GCMS notes to see the reasons for the interview request, and try to address their concerns at the interview.