Ladies am I wrong????

I need your advice ladies, I'm 17weeks 2days due 10/25with our babyboy💙💙, we are TRUELY excited. One problem I have this superstition within me that's drinking my fiancé crazy lol. I feel like until I'm 20weeks we can not bring anything into our house for our baby just yet. Am I crazy?? Soooooo we have everything so far at my moms house and his moms house. My fiancé wants to start the nursery like yesterday, we basically know what we want and what we love but I keep telling him CHRISTIAN NOT UNTIL IN 20WEEKS, he's like ok what's happening at 20weeks that isn't right now lol. Ughhhh ladies am I wrong, he feels 20weeks is starting very late? Is he right. My GYN tells us everything looks great so far, but why do I feel this way??!!!