Am I Crazy??

My wedding is in a little over a month and has been the most stressful and ridiculous ordeal I've ever had to deal with in my life. For the wedding, I'm wearing a cream colored dress, not white. My mother in law, who I normally get along well with but lately I feel has been overstepping her boundaries a bit, knows that my dress is cream, though she hasn't seen it. The other day, however, she sent me a video showing her in an outfit she was considering and asking if it would be okay if she wore cream to my wedding. Am I crazy or is this completely inappropriate?? I would never wear a color even remotely close to the "white" color family to someone else's wedding. Especially not a color that matches the bride. I'm just not sure if I'm having a "bridezilla" moment or if she's out of hand.