Should I wait?

So I am only in my fifth week of pregnancy and I have told my husband, mom, his mom, and a close friend. I had planned to wait the "proper 12 weeks?" To let everybody else know but my mom has told soooo many people I just don't know if I should wait? I'm glad she's excited, this is her first grandchild, but I just don't know what would be best? I really don't know the proper etiquette here and I'm worried if I don't go ahead and make it public myself people will just find out through the grape vine and maybe get offended? But on the other hand I really want to wait to make it public. What should I do?