I don't think there is anything wrong with throwing her a baby shower now and having her register for anything that she needs.
When I was pregnant with my 2nd child, I had already gotten rid of most of my baby items because we had live in a small apt and had moved a few times since the first baby. So, my sister-in-law threw me a shower and it was very nice :)I was able to get the playpen and tons of things that we still needed (clothes, diapers, monitor, toiletries & bath items, etc...). It's always nice getting things for a new baby.
As someone else has said, if someone doesn't want to attend another baby shower, then they don't have to :) But, I'm sure there will be plenty of people who would.