When is everyone registering for their shower?

Dawn
I am 12 weeks tomorrow and although my husband and I are super excited for our first baby, I am also afraid of getting too excited and jinxing the situation. I have found myself looking at baby things in the store but haven't gone as far as to buy anything yet. 
Because I am so excited and my sister just had a baby a week ago, I find myself wanting to start building a registery online. Probably not going to the stores yet, but at least adding things, reading reviews, etc online. 
When is everyone else planning to start doing that or have you already? Is it too soon?