Strep b positive and 3rd time due date change

So at today's appt let's just say not the news I wanted to hear😞 so as normal I get hooked on the monitor start having contractions then go to ultrasound everything's normal. Dr comes in checks me to see if I'm dialated due to the contration and nothing and throws in there that I'm strep b positive so no trying to make my water break on my own. I then proceeded to ask are we still trying to push for 38 weeks she said that they cant induce until 39 weeks which I didnt understand cause i had my son at 37 weeks. So now we have scheduled for inducing on the 20th of Nov.