A wedding is a two-way street. Sure, it's often regarded as the bride's time to shine, but there's also a groom involved (or a second bride, or no brides at all!).
That being said, you shouldn't let anyone push their "vision" of what your wedding should be. Especially if they aren't one of the people getting married. For one bride, though, her fiancé and future mother-in-law are wayyy too pushy.