Tink, I don't think it's too early. Our nursery was all decked out and completed at 16 weeks pregnant (it was a present from my departing parents-in-law whilst they were overseas for baby's birth) and I think I had our car seat & pram at around the same time too. I felt it was easier to do early because I wouldnt have a big bump in the way.

The 20% sounds fantastic! Go now and shoppeth!