Mucus plug at 31 weeks???

Shan • Soon to be mommy of two 👦🏽👶🏽 #Jan2017babies 👨‍👩‍👧‍👦💙💛
Alrighty so today at work I wiped myself and noticed the discharge. I didn't lose one in my first pregnancy so I have no idea if this is it or if I am going crazy. I will be 31 weeks on Friday. Should I start preparing for baby? What should I do?