nursery help!!!

Michelle • Expecting my first baby girl, Arya Rose, in June 2017! 💜
I keep getting told by many different people that 21 weeks is too early to start the nursery shopping. But I HATE waiting until the last minute. Opinions on starting the nursery now instead of later when I'm too tired to do much??
Also!! Anyone know any good sites for crib bedding? I've looked on Overstock, Wayfair, and babies r us.