Mine's on amazon, so I started it super early without telling anyone about it, just to get ideas. Now that I know we're having a girl I'm editing it and adding more specific stuff (before I just had a few crib sets that I liked and a travel system).
I started already. This is my first baby and no matter the sex, there are some things (equipment like strollers, seats, bassinet, etc) that we want to be gender neutral. Should we be blessed with another baby after this, I would like to be able to re-use things even if the babies are different sexes. So we started building a registry, it has been fun. Haven't told anyone about the registries yet except my parents. We are doing babies r us and Amazon.com.
I already got mine one at babies-r-us and one at target ( they give a register gift when you finish signing up )
That's when I was thinking of doing it. I just have to find places that allow my friends and family to buy it at a store and then me and my husband pick it up at the same store in our state. We live 13 hours from our original home but the shower is there .
I plan to start mine as soon as we know the sex. Most of my family and friends live over a thousand miles away do they won't be able to make it to the shower later on. They all want time to shop and send. I'd say whenever you are excited and ready to do it. If you aren't ready to share with people tjat its ready just wait to let people know!