How to politely decline help with nursery

My mom is in town and wants to help me put my nursery together. I was all for it at first but now she’s basically trying to take over everything and it’s really bothering me. I feel like she’s taking the whole thing away from me and all I want to do is be alone in my baby’s room and organize the way it makes sense to me. I don’t want to hurt her feelings but I don’t know how to keep politely declining every piece of advice she’s shoving down my throat. I’m feel like I’m going insane.