Hi! I'm glad tp hear that you did all those great things with your baby!
The reasoning behind not putting a hat on a newborn baby is that, immediately after birth, the mother needs to take in the scent of her newborn baby in constantly. Smelling the baby's head releases hormones to help the mother's uterus contract, expel the placenta and prevent excessive bleeding. The baby's warmth is taken care of when it's skin-to-skin with mom, so a hat is not imperative for warmth immediately after birth.
But there's nothing wrong with a hat the day after birth!
RE: The 10 Most Important Questions to Ask Your Pregnancy Care Provider