Baby registry (easy)?

My mom wants me to get a basic registry put together so she can budget to get the baby some things. She wants to know what kinds of furniture I want, ect. That being said, should I start my registry now, or wait until I actually conceive, and just tell her what I have in mind, rather than starting a registry? Also, my fiancee wants to throw the baby shower for me, he knows what I like best. And he's very excited to be a father, but from what I've read/heard/and have learned over the years. It is considered socially improper to hold your own shower. How do I tell him that kindly?