Ginger appears different, depending on when it was harvested. The longer it has been left in the ground the thicker the skin and the more intense the heat. Old ginger isn't to be confused with shriveled up half dead ginger found in the bottom of the supermarket pile. That is just young ginger or normal ginger that's going to go rotten soon.
The idea of ginger in confinement food is that it will help to expel gas that you may have and generate heat for your body, which may be cold now that the baby has left the inside of you. It also helps to make the uterus cramp to contract down, so in the days after giving birth when you drink the ginger tea it has the same after sensation as breastfeeding, where the uterus cramps down and you get a rush of lochia.