100% effaced but cervix still closed?

I'm due oct 13 and I've had a short cervix since my 30 week ultrasound and was in pre term labor last week but doctor stopped it and I was only 50% effaced last week now I had a appointment today and my dr told me I'm 100% effaced my cervix is completely thinned but still very closed. What exactly does this mean? Does it mean I'll go into labor soon or can I be effaced for a couple weeks I also havnt seen my mucus plug come out I will be 37 weeks in a few days. Any one go through this or experiencing this I'm ftm and confused