It may help, but if you've already told them you plan to go marry your boyfriend, I don't see them changing their minds.
Also, getting married on the first visit is a red flag too.
Have you looked at other options to come to Canada so you and your boyfriend can live together for a while? That way you will have cohabitation as proof for your application. Living together unmarried is legal in Canada, so there's no issue with that part. Plus it will give you time to test the relationship and make sure it's right for you. (Just a personal tip - I met both of my husbands online. Online relationships are a lot easier than in person. In person you actually have to deal with the little things your husband does that annoy you... like leave empty coffee cups all over the house.
It's good to be together IRL for a little while to make sure the relationship is right for you.)