Controlling grandparents .. Anyone else?

I knew my mom would eventually get annoyed by something my fiancé and I would decide on .. She's one of those moms that doesn't like it when people do something other than what she thinks is right. My fiancé & I decided that we didn't want to announce the gender until after the baby shower because we want people to actually buy things off of our registry instead of ending up with a bunch of pink or blue clothes that the baby will probably never wear. We're actually going to do the gender reveal at the end of the shower (something exciting for guests to look forward to!) When I told my mom this today on the phone her mood went from happy to annoyed, arguing with me about "how is she supposed to plan a baby shower without knowing the sex?" And then abruptly ended the phone call. & it starts ..